31977389 has 2 divisors, whose sum is σ = 31977390. Its totient is φ = 31977388.

The previous prime is 31977373. The next prime is 31977403. The reversal of 31977389 is 98377913.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 30858025 + 1119364 = 5555^2 + 1058^2 .

It is a cyclic number.

It is not a de Polignac number, because 31977389 - 2⁴ = 31977373 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31977329) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15988694 + 15988695.

It is an arithmetic number, because the mean of its divisors is an integer number (15988695).

Almost surely, 2^31977389 is an apocalyptic number.

It is an amenable number.

31977389 is a deficient number, since it is larger than the sum of its proper divisors (1).

31977389 is an equidigital number, since it uses as much as digits as its factorization.

31977389 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 285768, while the sum is 47.

The square root of 31977389 is about 5654.8553473984. The cubic root of 31977389 is about 317.4054162637.

The spelling of 31977389 in words is "thirty-one million, nine hundred seventy-seven thousand, three hundred eighty-nine".