20565100 has 18 divisors (see below), whose sum is σ = 44626484. Its totient is φ = 8226000.

The previous prime is 20565091. The next prime is 20565101. The reversal of 20565100 is 156502.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (20565101) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 102726 + ... + 102925.

Almost surely, 2^20565100 is an apocalyptic number.

20565100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20565100 is an abundant number, since it is smaller than the sum of its proper divisors (24061384).

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

20565100 is a wasteful number, since it uses less digits than its factorization.

20565100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 205665 (or 205658 counting only the distinct ones).

The product of its (nonzero) digits is 300, while the sum is 19.

The square root of 20565100 is about 4534.8759630226. The cubic root of 20565100 is about 273.9745833955.

The spelling of 20565100 in words is "twenty million, five hundred sixty-five thousand, one hundred".