31739989 has 2 divisors, whose sum is σ = 31739990. Its totient is φ = 31739988.

The previous prime is 31739987. The next prime is 31740011. The reversal of 31739989 is 98993713.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16200625 + 15539364 = 4025^2 + 3942^2 .

It is a cyclic number.

It is not a de Polignac number, because 31739989 - 2¹ = 31739987 is a prime.

Together with 31739987, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31739987) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15869994 + 15869995.

It is an arithmetic number, because the mean of its divisors is an integer number (15869995).

Almost surely, 2^31739989 is an apocalyptic number.

It is an amenable number.

31739989 is a deficient number, since it is larger than the sum of its proper divisors (1).

31739989 is an equidigital number, since it uses as much as digits as its factorization.

31739989 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 367416, while the sum is 49.

The square root of 31739989 is about 5633.8254321553. The cubic root of 31739989 is about 316.6179922725.

The spelling of 31739989 in words is "thirty-one million, seven hundred thirty-nine thousand, nine hundred eighty-nine".