31680731 has 8 divisors (see below), whose sum is σ = 32865600. Its totient is φ = 30502080.

The previous prime is 31680721. The next prime is 31680743. The reversal of 31680731 is 13708613.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-31680731 is a prime.

It is a super-2 number, since 2×31680731² = 2007337433388722, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (29).

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 31680694 and 31680703.

It is not an unprimeable number, because it can be changed into a prime (31680721) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10526 + ... + 13196.

It is an arithmetic number, because the mean of its divisors is an integer number (4108200).

Almost surely, 2^31680731 is an apocalyptic number.

31680731 is a deficient number, since it is larger than the sum of its proper divisors (1184869).

31680731 is a wasteful number, since it uses less digits than its factorization.

31680731 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3109.

The product of its (nonzero) digits is 3024, while the sum is 29.

The square root of 31680731 is about 5628.5638487984. The cubic root of 31680731 is about 316.4208294514.

The spelling of 31680731 in words is "thirty-one million, six hundred eighty thousand, seven hundred thirty-one".