20565400 has 72 divisors (see below), whose sum is σ = 49868460. Its totient is φ = 7886400.

The previous prime is 20565383. The next prime is 20565403. The reversal of 20565400 is 456502.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20565403) 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 17 ways as a sum of consecutive naturals, for example, 192147 + ... + 192253.

Almost surely, 2^20565400 is an apocalyptic number.

20565400 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 20565400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24934230).

20565400 is an abundant number, since it is smaller than the sum of its proper divisors (29303060).

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

20565400 is a wasteful number, since it uses less digits than its factorization.

20565400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 185 (or 145 counting only the distinct ones).

The product of its (nonzero) digits is 1200, while the sum is 22.

The square root of 20565400 is about 4534.9090398816. The cubic root of 20565400 is about 273.9759156198.

The spelling of 20565400 in words is "twenty million, five hundred sixty-five thousand, four hundred".