6420816900 has 81 divisors (see below), whose sum is σ = 20133231573. Its totient is φ = 1711576800.

The previous prime is 6420816869. The next prime is 6420816901. The reversal of 6420816900 is 96180246.

The square root of 6420816900 is 80130.

It is a perfect power (a square), and thus also a powerful number.

6420816900 is a `hidden beast` number, since 642 + 0 + 8 + 1 + 6 + 9 + 0 + 0 = 666.

It can be written as a sum of positive squares in only one way, i.e., 2311494084 + 4109322816 = 48078^2 + 64104^2 .

It is a super-2 number, since 2×6420816900² = 82453779326651220000, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is not an unprimeable number, because it can be changed into a prime (6420816901) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 2402565 + ... + 2405235.

Almost surely, 2^6420816900 is an apocalyptic number.

6420816900 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

6420816900 is the 80130-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 6420816900

6420816900 is an abundant number, since it is smaller than the sum of its proper divisors (13712414673).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

6420816900 is a wasteful number, since it uses less digits than its factorization.

6420816900 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5362 (or 2681 counting only the distinct ones).

The product of its (nonzero) digits is 20736, while the sum is 36.

The cubic root of 6420816900 is about 1858.6463442574.

Multiplying 6420816900 by its sum of digits (36), we get a square (231149408400 = 480780²).

6420816900 divided by its sum of digits (36) gives a square (178356025 = 13355²).

Multiplying 6420816900 by its product of nonzero digits (20736), we get a square (133142059238400 = 11538720²).

The spelling of 6420816900 in words is "six billion, four hundred twenty million, eight hundred sixteen thousand, nine hundred".