31287680 has 128 divisors (see below), whose sum is σ = 82252800. Its totient is φ = 11335680.

The previous prime is 31287677. The next prime is 31287689. The reversal of 31287680 is 8678213.

It is a tau number, because it is divible by the number of its divisors (128).

It is a self number, because there is not a number n which added to its sum of digits gives 31287680.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31287689) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 376919 + ... + 377001.

It is an arithmetic number, because the mean of its divisors is an integer number (642600).

Almost surely, 2^31287680 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 31287680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (41126400).

31287680 is an abundant number, since it is smaller than the sum of its proper divisors (50965120).

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

31287680 is a wasteful number, since it uses less digits than its factorization.

31287680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 152 (or 140 counting only the distinct ones).

The product of its (nonzero) digits is 16128, while the sum is 35.

The square root of 31287680 is about 5593.5391301036. The cubic root of 31287680 is about 315.1068084931.

The spelling of 31287680 in words is "thirty-one million, two hundred eighty-seven thousand, six hundred eighty".