31420721772 has 48 divisors (see below), whose sum is σ = 88866691200. Its totient is φ = 9521430480.

The previous prime is 31420721749. The next prime is 31420721791. The reversal of 31420721772 is 27712702413.

It is a Harshad number since it is a multiple of its sum of digits (36).

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, 13223022 + ... + 13225397.

It is an arithmetic number, because the mean of its divisors is an integer number (1851389400).

Almost surely, 2^31420721772 is an apocalyptic number.

It is an amenable number.

31420721772 is an abundant number, since it is smaller than the sum of its proper divisors (57445969428).

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

31420721772 is a wasteful number, since it uses less digits than its factorization.

31420721772 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26448443 (or 26448435 counting only the distinct ones).

The product of its (nonzero) digits is 32928, while the sum is 36.

The spelling of 31420721772 in words is "thirty-one billion, four hundred twenty million, seven hundred twenty-one thousand, seven hundred seventy-two".