21712182920 has 16 divisors (see below), whose sum is σ = 48852411660. Its totient is φ = 8684873152.

The previous prime is 21712182887. The next prime is 21712182977. The reversal of 21712182920 is 2928121712.

It can be written as a sum of positive squares in 2 ways, for example, as 18693999076 + 3018183844 = 136726^2 + 54938^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 271402247 + ... + 271402326.

Almost surely, 2^21712182920 is an apocalyptic number.

21712182920 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21712182920 is an abundant number, since it is smaller than the sum of its proper divisors (27140228740).

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

21712182920 is a wasteful number, since it uses less digits than its factorization.

21712182920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 542804584 (or 542804580 counting only the distinct ones).

The product of its (nonzero) digits is 8064, while the sum is 35.

The spelling of 21712182920 in words is "twenty-one billion, seven hundred twelve million, one hundred eighty-two thousand, nine hundred twenty".