21975173911920 has 80 divisors (see below), whose sum is σ = 68202529892640. Its totient is φ = 5853208461312.

The previous prime is 21975173911903. The next prime is 21975173911939. The reversal of 21975173911920 is 2911937157912.

It is a tau number, because it is divible by the number of its divisors (80).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 53215105 + ... + 53626464.

It is an arithmetic number, because the mean of its divisors is an integer number (852531623658).

Almost surely, 2^{21975173911920} is an apocalyptic number.

21975173911920 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21975173911920 is an abundant number, since it is smaller than the sum of its proper divisors (46227355980720).

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

21975173911920 is a wasteful number, since it uses less digits than its factorization.

21975173911920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 106842442 (or 106842436 counting only the distinct ones).

The product of its (nonzero) digits is 2143260, while the sum is 57.

The spelling of 21975173911920 in words is "twenty-one trillion, nine hundred seventy-five billion, one hundred seventy-three million, nine hundred eleven thousand, nine hundred twenty".