20816100 has 108 divisors (see below), whose sum is σ = 66180660. Its totient is φ = 5472000.

The previous prime is 20816099. The next prime is 20816111. The reversal of 20816100 is 161802.

It can be written as a sum of positive squares in 6 ways, for example, as 3326976 + 17489124 = 1824^2 + 4182^2 .

It is a Harshad number since it is a multiple of its sum of digits (18).

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 90786 + ... + 91014.

Almost surely, 2^20816100 is an apocalyptic number.

20816100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20816100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33090330).

20816100 is an abundant number, since it is smaller than the sum of its proper divisors (45364560).

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

20816100 is a wasteful number, since it uses less digits than its factorization.

20816100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 350 (or 340 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 18.

The square root of 20816100 is about 4562.4664382327. The cubic root of 20816100 is about 275.0847121942.

Adding to 20816100 its reverse (161802), we get a palindrome (20977902).

The spelling of 20816100 in words is "twenty million, eight hundred sixteen thousand, one hundred".