21480557856 has 24 divisors (see below), whose sum is σ = 56386464624. Its totient is φ = 7160185920.

The previous prime is 21480557797. The next prime is 21480557867. The reversal of 21480557856 is 65875508412.

It is a tau number, because it is divible by the number of its divisors (24).

It is a super-2 number, since 2×21480557856² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21480557799 and 21480557808.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 111877810 + ... + 111878001.

It is an arithmetic number, because the mean of its divisors is an integer number (2349436026).

Almost surely, 2^21480557856 is an apocalyptic number.

It is an amenable number.

21480557856 is an abundant number, since it is smaller than the sum of its proper divisors (34905906768).

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

21480557856 is a wasteful number, since it uses less digits than its factorization.

21480557856 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 223755824 (or 223755816 counting only the distinct ones).

The product of its (nonzero) digits is 2688000, while the sum is 51.

The spelling of 21480557856 in words is "twenty-one billion, four hundred eighty million, five hundred fifty-seven thousand, eight hundred fifty-six".