21549982856 has 64 divisors (see below), whose sum is σ = 43705780800. Its totient is φ = 9928396800.

The previous prime is 21549982849. The next prime is 21549982877. The reversal of 21549982856 is 65828994512.

It is a super-2 number, since 2×21549982856² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21549982795 and 21549982804.

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 1568336 + ... + 1582016.

It is an arithmetic number, because the mean of its divisors is an integer number (682902825).

Almost surely, 2^21549982856 is an apocalyptic number.

It is an amenable number.

21549982856 is an abundant number, since it is smaller than the sum of its proper divisors (22155797944).

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

21549982856 is a wasteful number, since it uses less digits than its factorization.

21549982856 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13990 (or 13986 counting only the distinct ones).

The product of its digits is 12441600, while the sum is 59.

The spelling of 21549982856 in words is "twenty-one billion, five hundred forty-nine million, nine hundred eighty-two thousand, eight hundred fifty-six".