21572400 has 60 divisors (see below), whose sum is σ = 69107432. Its totient is φ = 5752320.

The previous prime is 21572387. The next prime is 21572401. The reversal of 21572400 is 427512.

It is a tau number, because it is divible by the number of its divisors (60).

It is not an unprimeable number, because it can be changed into a prime (21572401) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 7789 + ... + 10188.

Almost surely, 2^21572400 is an apocalyptic number.

21572400 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21572400 is an abundant number, since it is smaller than the sum of its proper divisors (47535032).

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

21572400 is a wasteful number, since it uses less digits than its factorization.

21572400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17998 (or 17987 counting only the distinct ones).

The product of its (nonzero) digits is 560, while the sum is 21.

The square root of 21572400 is about 4644.6097790880. The cubic root of 21572400 is about 278.3766610769.

Adding to 21572400 its reverse (427512), we get a palindrome (21999912).

The spelling of 21572400 in words is "twenty-one million, five hundred seventy-two thousand, four hundred".