31559989 has 2 divisors, whose sum is σ = 31559990. Its totient is φ = 31559988.

The previous prime is 31559981. The next prime is 31560019. The reversal of 31559989 is 98995513.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17497489 + 14062500 = 4183^2 + 3750^2 .

It is a cyclic number.

It is not a de Polignac number, because 31559989 - 2³ = 31559981 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31559981) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15779994 + 15779995.

It is an arithmetic number, because the mean of its divisors is an integer number (15779995).

Almost surely, 2^31559989 is an apocalyptic number.

It is an amenable number.

31559989 is a deficient number, since it is larger than the sum of its proper divisors (1).

31559989 is an equidigital number, since it uses as much as digits as its factorization.

31559989 is an evil number, because the sum of its binary digits is even.

The product of its digits is 437400, while the sum is 49.

The square root of 31559989 is about 5617.8277830492. The cubic root of 31559989 is about 316.0183353405.

The spelling of 31559989 in words is "thirty-one million, five hundred fifty-nine thousand, nine hundred eighty-nine".