21756039456 has 24 divisors (see below), whose sum is σ = 57109603824. Its totient is φ = 7252013120.

The previous prime is 21756039427. The next prime is 21756039497. The reversal of 21756039456 is 65493065712.

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

It is a super-2 number, since 2×21756039456² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (48).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 113312610 + ... + 113312801.

It is an arithmetic number, because the mean of its divisors is an integer number (2379566826).

Almost surely, 2^21756039456 is an apocalyptic number.

It is an amenable number.

21756039456 is an abundant number, since it is smaller than the sum of its proper divisors (35353564368).

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

21756039456 is a wasteful number, since it uses less digits than its factorization.

21756039456 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 226625424 (or 226625416 counting only the distinct ones).

The product of its (nonzero) digits is 1360800, while the sum is 48.

The spelling of 21756039456 in words is "twenty-one billion, seven hundred fifty-six million, thirty-nine thousand, four hundred fifty-six".