31690487 has 2 divisors, whose sum is σ = 31690488. Its totient is φ = 31690486.

The previous prime is 31690447. The next prime is 31690489. The reversal of 31690487 is 78409613.

It is a strong prime.

It is an emirp because it is prime and its reverse (78409613) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 31690487 - 2⁸ = 31690231 is a prime.

Together with 31690489, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 31690487.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31690489) by changing a digit.

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 as a sum of consecutive naturals, namely, 15845243 + 15845244.

It is an arithmetic number, because the mean of its divisors is an integer number (15845244).

Almost surely, 2^31690487 is an apocalyptic number.

31690487 is a deficient number, since it is larger than the sum of its proper divisors (1).

31690487 is an equidigital number, since it uses as much as digits as its factorization.

31690487 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 36288, while the sum is 38.

The square root of 31690487 is about 5629.4304330012. The cubic root of 31690487 is about 316.4533064460.

The spelling of 31690487 in words is "thirty-one million, six hundred ninety thousand, four hundred eighty-seven".