31688617 has 2 divisors, whose sum is σ = 31688618. Its totient is φ = 31688616.

The previous prime is 31688611. The next prime is 31688621. The reversal of 31688617 is 71688613.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 30239001 + 1449616 = 5499^2 + 1204^2 .

It is a cyclic number.

It is not a de Polignac number, because 31688617 - 2³ = 31688609 is a prime.

It is a super-3 number, since 3×31688617³ (a number of 23 digits) contains 333 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 31688617.

It is not a weakly prime, because it can be changed into another prime (31688611) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15844308 + 15844309.

It is an arithmetic number, because the mean of its divisors is an integer number (15844309).

Almost surely, 2^31688617 is an apocalyptic number.

It is an amenable number.

31688617 is a deficient number, since it is larger than the sum of its proper divisors (1).

31688617 is an equidigital number, since it uses as much as digits as its factorization.

31688617 is an evil number, because the sum of its binary digits is even.

The product of its digits is 48384, while the sum is 40.

The square root of 31688617 is about 5629.2643391477. The cubic root of 31688617 is about 316.4470818723.

The spelling of 31688617 in words is "thirty-one million, six hundred eighty-eight thousand, six hundred seventeen".