31031989 has 2 divisors, whose sum is σ = 31031990. Its totient is φ = 31031988.

The previous prime is 31031983. The next prime is 31032017. The reversal of 31031989 is 98913013.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 30891364 + 140625 = 5558^2 + 375^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-31031989 is a prime.

It is a super-2 number, since 2×31031989² = 1925968682592242, which contains 22 as substring.

It is equal to p_1917844 and since 31031989 and 1917844 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31031983) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15515994 + 15515995.

It is an arithmetic number, because the mean of its divisors is an integer number (15515995).

Almost surely, 2^31031989 is an apocalyptic number.

It is an amenable number.

31031989 is a deficient number, since it is larger than the sum of its proper divisors (1).

31031989 is an equidigital number, since it uses as much as digits as its factorization.

31031989 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5832, while the sum is 34.

The square root of 31031989 is about 5570.6363191291. The cubic root of 31031989 is about 314.2460814545.

The spelling of 31031989 in words is "thirty-one million, thirty-one thousand, nine hundred eighty-nine".