31488991 has 2 divisors, whose sum is σ = 31488992. Its totient is φ = 31488990.

The previous prime is 31488979. The next prime is 31489009. The reversal of 31488991 is 19988413.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 31488991 - 2⁵ = 31488959 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31488911) 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, 15744495 + 15744496.

It is an arithmetic number, because the mean of its divisors is an integer number (15744496).

Almost surely, 2^31488991 is an apocalyptic number.

31488991 is a deficient number, since it is larger than the sum of its proper divisors (1).

31488991 is an equidigital number, since it uses as much as digits as its factorization.

31488991 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 62208, while the sum is 43.

The square root of 31488991 is about 5611.5052347833. The cubic root of 31488991 is about 315.7811836367.

The spelling of 31488991 in words is "thirty-one million, four hundred eighty-eight thousand, nine hundred ninety-one".