20931870918 has 32 divisors (see below), whose sum is σ = 48137815296. Its totient is φ = 5943842208.

The previous prime is 20931870901. The next prime is 20931870989. The reversal of 20931870918 is 81907813902.

It is a Smith number, since the sum of its digits (48) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

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, 1521921 + ... + 1535612.

It is an arithmetic number, because the mean of its divisors is an integer number (1504306728).

Almost surely, 2^20931870918 is an apocalyptic number.

20931870918 is an abundant number, since it is smaller than the sum of its proper divisors (27205944378).

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

20931870918 is a wasteful number, since it uses less digits than its factorization.

20931870918 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3057708.

The product of its (nonzero) digits is 217728, while the sum is 48.

The spelling of 20931870918 in words is "twenty billion, nine hundred thirty-one million, eight hundred seventy thousand, nine hundred eighteen".