20621255928 has 64 divisors (see below), whose sum is σ = 63450024960. Its totient is φ = 5438572416.

The previous prime is 20621255923. The next prime is 20621256011. The reversal of 20621255928 is 82955212602.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a self number, because there is not a number n which added to its sum of digits gives 20621255928.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20621255923) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4718800 + ... + 4723167.

It is an arithmetic number, because the mean of its divisors is an integer number (991406640).

Almost surely, 2^20621255928 is an apocalyptic number.

20621255928 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

20621255928 is an abundant number, since it is smaller than the sum of its proper divisors (42828769032).

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

20621255928 is a wasteful number, since it uses less digits than its factorization.

20621255928 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9441996 (or 9441992 counting only the distinct ones).

The product of its (nonzero) digits is 172800, while the sum is 42.

The spelling of 20621255928 in words is "twenty billion, six hundred twenty-one million, two hundred fifty-five thousand, nine hundred twenty-eight".