31391316 has 72 divisors (see below), whose sum is σ = 91675584. Its totient is φ = 8951040.

The previous prime is 31391303. The next prime is 31391329. The reversal of 31391316 is 61319313.

It is an interprime number because it is at equal distance from previous prime (31391303) and next prime (31391329).

It is a nude number because it is divisible by every one of its digits.

It is a self number, because there is not a number n which added to its sum of digits gives 31391316.

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 23 ways as a sum of consecutive naturals, for example, 4401 + ... + 9063.

It is an arithmetic number, because the mean of its divisors is an integer number (1273272).

Almost surely, 2^31391316 is an apocalyptic number.

31391316 is a gapful number since it is divisible by the number (36) 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 31391316, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (45837792).

31391316 is an abundant number, since it is smaller than the sum of its proper divisors (60284268).

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

31391316 is a wasteful number, since it uses less digits than its factorization.

31391316 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4701 (or 4696 counting only the distinct ones).

The product of its digits is 1458, while the sum is 27.

The square root of 31391316 is about 5602.7953737398. The cubic root of 31391316 is about 315.4543405870.

The spelling of 31391316 in words is "thirty-one million, three hundred ninety-one thousand, three hundred sixteen".