31897728720 has 800 divisors, whose sum is σ = 134755125120. Its totient is φ = 6886010880.

The previous prime is 31897728689. The next prime is 31897728743. The reversal of 31897728720 is 2782779813.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 159 ways as a sum of consecutive naturals, for example, 26871967 + ... + 26873153.

Almost surely, 2^31897728720 is an apocalyptic number.

31897728720 is a gapful number since it is divisible by the number (30) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 31897728720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (67377562560).

31897728720 is an abundant number, since it is smaller than the sum of its proper divisors (102857396400).

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

31897728720 is a wasteful number, since it uses less digits than its factorization.

31897728720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1265 (or 1250 counting only the distinct ones).

The product of its (nonzero) digits is 2370816, while the sum is 54.

The spelling of 31897728720 in words is "thirty-one billion, eight hundred ninety-seven million, seven hundred twenty-eight thousand, seven hundred twenty".