31891991040 has 1440 divisors, whose sum is σ = 144416288016. Its totient is φ = 6440878080.

The previous prime is 31891991023. The next prime is 31891991063. The reversal of 31891991040 is 4019919813.

It can be written as a sum of positive squares in 8 ways, for example, as 3780774144 + 28111216896 = 61488^2 + 167664^2 .

It is a tau number, because it is divible by the number of its divisors (1440).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 601735654 + ... + 601735706.

Almost surely, 2^31891991040 is an apocalyptic number.

31891991040 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 31891991040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (72208144008).

31891991040 is an abundant number, since it is smaller than the sum of its proper divisors (112524296976).

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

31891991040 is a wasteful number, since it uses less digits than its factorization.

31891991040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 150 (or 124 counting only the distinct ones).

The product of its (nonzero) digits is 69984, while the sum is 45.

The spelling of 31891991040 in words is "thirty-one billion, eight hundred ninety-one million, nine hundred ninety-one thousand, forty".