31491587 has 2 divisors, whose sum is σ = 31491588. Its totient is φ = 31491586.

The previous prime is 31491571. The next prime is 31491589. The reversal of 31491587 is 78519413.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 31491587 - 2⁴ = 31491571 is a prime.

Together with 31491589, 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 31491587.

It is not a weakly prime, because it can be changed into another prime (31491589) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15745793 + 15745794.

It is an arithmetic number, because the mean of its divisors is an integer number (15745794).

Almost surely, 2^31491587 is an apocalyptic number.

31491587 is a deficient number, since it is larger than the sum of its proper divisors (1).

31491587 is an equidigital number, since it uses as much as digits as its factorization.

31491587 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 30240, while the sum is 38.

The square root of 31491587 is about 5611.7365405015. The cubic root of 31491587 is about 315.7898612242.

The spelling of 31491587 in words is "thirty-one million, four hundred ninety-one thousand, five hundred eighty-seven".