20646100 has 18 divisors (see below), whose sum is σ = 44802254. Its totient is φ = 8258400.

The previous prime is 20646091. The next prime is 20646107. The reversal of 20646100 is 164602.

It can be written as a sum of positive squares in 3 ways, for example, as 611524 + 20034576 = 782^2 + 4476^2 .

It is a super-2 number, since 2×20646100² = 852522890420000, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20646107) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 103131 + ... + 103330.

Almost surely, 2^20646100 is an apocalyptic number.

20646100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20646100 is an abundant number, since it is smaller than the sum of its proper divisors (24156154).

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

20646100 is a wasteful number, since it uses less digits than its factorization.

20646100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 206475 (or 206468 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 19.

The square root of 20646100 is about 4543.7979708609. The cubic root of 20646100 is about 274.3338144707. Note that the first 3 decimals are identical.

The spelling of 20646100 in words is "twenty million, six hundred forty-six thousand, one hundred".