21256473600 has 924 divisors, whose sum is σ = 84894805224. Its totient is φ = 5255331840.

The previous prime is 21256473587. The next prime is 21256473643. The reversal of 21256473600 is 637465212.

21256473600 is a `hidden beast` number, since 2 + 1 + 2 + 5 + 6 + 47 + 3 + 600 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a polite number, since it can be written in 83 ways as a sum of consecutive naturals, for example, 317260767 + ... + 317260833.

Almost surely, 2^21256473600 is an apocalyptic number.

21256473600 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 21256473600, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (42447402612).

21256473600 is an abundant number, since it is smaller than the sum of its proper divisors (63638331624).

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

21256473600 is an equidigital number, since it uses as much as digits as its factorization.

21256473600 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 132 (or 94 counting only the distinct ones).

The product of its (nonzero) digits is 60480, while the sum is 36.

The spelling of 21256473600 in words is "twenty-one billion, two hundred fifty-six million, four hundred seventy-three thousand, six hundred".