31387680 has 144 divisors (see below), whose sum is σ = 108972864. Its totient is φ = 8225280.

The previous prime is 31387679. The next prime is 31387693. The reversal of 31387680 is 8678313.

It is a tau number, because it is divible by the number of its divisors (144).

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 23 ways as a sum of consecutive naturals, for example, 102087 + ... + 102393.

It is an arithmetic number, because the mean of its divisors is an integer number (756756).

Almost surely, 2^31387680 is an apocalyptic number.

31387680 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 31387680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (54486432).

31387680 is an abundant number, since it is smaller than the sum of its proper divisors (77585184).

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

31387680 is a wasteful number, since it uses less digits than its factorization.

31387680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 399 (or 388 counting only the distinct ones).

The product of its (nonzero) digits is 24192, while the sum is 36.

The square root of 31387680 is about 5602.4708834585. The cubic root of 31387680 is about 315.4421606127.

The spelling of 31387680 in words is "thirty-one million, three hundred eighty-seven thousand, six hundred eighty".