20564100 has 108 divisors (see below), whose sum is σ = 65548756. Its totient is φ = 5391360.

The previous prime is 20564087. The next prime is 20564113. The reversal of 20564100 is 146502.

It is a happy number.

20564100 is a `hidden beast` number, since 2 + 0 + 564 + 100 = 666.

It is an interprime number because it is at equal distance from previous prime (20564087) and next prime (20564113).

It can be written as a sum of positive squares in 6 ways, for example, as 4064256 + 16499844 = 2016^2 + 4062^2 .

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, 65544 + ... + 65856.

Almost surely, 2^20564100 is an apocalyptic number.

20564100 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 20564100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32774378).

20564100 is an abundant number, since it is smaller than the sum of its proper divisors (44984656).

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

20564100 is a wasteful number, since it uses less digits than its factorization.

20564100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 406 (or 396 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 18.

The square root of 20564100 is about 4534.7657050833. The cubic root of 20564100 is about 273.9701425544.

The spelling of 20564100 in words is "twenty million, five hundred sixty-four thousand, one hundred".