31997609280 has 448 divisors, whose sum is σ = 138933204480. Its totient is φ = 6750978048.

The previous prime is 31997609227. The next prime is 31997609309. The reversal of 31997609280 is 8290679913.

31997609280 is a `hidden beast` number, since 3 + 1 + 9 + 9 + 7 + 609 + 28 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (448).

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 polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 765892 + ... + 806588.

It is an arithmetic number, because the mean of its divisors is an integer number (310118760).

Almost surely, 2^31997609280 is an apocalyptic number.

31997609280 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 31997609280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (69466602240).

31997609280 is an abundant number, since it is smaller than the sum of its proper divisors (106935595200).

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

31997609280 is a wasteful number, since it uses less digits than its factorization.

31997609280 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40743 (or 40727 counting only the distinct ones).

The product of its (nonzero) digits is 1469664, while the sum is 54.

The spelling of 31997609280 in words is "thirty-one billion, nine hundred ninety-seven million, six hundred nine thousand, two hundred eighty".