21677840256 has 64 divisors (see below), whose sum is σ = 57963254400. Its totient is φ = 7178073600.

The previous prime is 21677840237. The next prime is 21677840269. The reversal of 21677840256 is 65204877612.

It is a tau number, because it is divible by the number of its divisors (64).

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

It is a congruent number.

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 7 ways as a sum of consecutive naturals, for example, 128946 + ... + 244913.

It is an arithmetic number, because the mean of its divisors is an integer number (905675850).

Almost surely, 2^21677840256 is an apocalyptic number.

It is an amenable number.

21677840256 is an abundant number, since it is smaller than the sum of its proper divisors (36285414144).

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

21677840256 is a wasteful number, since it uses less digits than its factorization.

21677840256 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 374027 (or 374015 counting only the distinct ones).

The product of its (nonzero) digits is 1128960, while the sum is 48.

The spelling of 21677840256 in words is "twenty-one billion, six hundred seventy-seven million, eight hundred forty thousand, two hundred fifty-six".