21255680928 has 24 divisors (see below), whose sum is σ = 55796162688. Its totient is φ = 7085226944.

The previous prime is 21255680921. The next prime is 21255680939. The reversal of 21255680928 is 82908655212.

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

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

It is not an unprimeable number, because it can be changed into a prime (21255680921) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 110706576 + ... + 110706767.

It is an arithmetic number, because the mean of its divisors is an integer number (2324840112).

Almost surely, 2^21255680928 is an apocalyptic number.

It is an amenable number.

21255680928 is an abundant number, since it is smaller than the sum of its proper divisors (34540481760).

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

21255680928 is a wasteful number, since it uses less digits than its factorization.

21255680928 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 221413356 (or 221413348 counting only the distinct ones).

The product of its (nonzero) digits is 691200, while the sum is 48.

The spelling of 21255680928 in words is "twenty-one billion, two hundred fifty-five million, six hundred eighty thousand, nine hundred twenty-eight".