21056418504 has 256 divisors, whose sum is σ = 66363321600. Its totient is φ = 6206181120.

The previous prime is 21056418499. The next prime is 21056418527. The reversal of 21056418504 is 40581465012.

It is a happy number.

21056418504 is a `hidden beast` number, since 2 + 1 + 0 + 5 + 641 + 8 + 5 + 0 + 4 = 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 63 ways as a sum of consecutive naturals, for example, 7119394 + ... + 7122350.

It is an arithmetic number, because the mean of its divisors is an integer number (259231725).

Almost surely, 2^21056418504 is an apocalyptic number.

21056418504 is a gapful number since it is divisible by the number (24) 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 21056418504, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33181660800).

21056418504 is an abundant number, since it is smaller than the sum of its proper divisors (45306903096).

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

21056418504 is a wasteful number, since it uses less digits than its factorization.

21056418504 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3032 (or 3010 counting only the distinct ones).

The product of its (nonzero) digits is 38400, while the sum is 36.

The spelling of 21056418504 in words is "twenty-one billion, fifty-six million, four hundred eighteen thousand, five hundred four".