31297639 has 2 divisors, whose sum is σ = 31297640. Its totient is φ = 31297638.

The previous prime is 31297573. The next prime is 31297661. The reversal of 31297639 is 93679213.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 31297639 - 2⁹ = 31297127 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31297139) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15648819 + 15648820.

It is an arithmetic number, because the mean of its divisors is an integer number (15648820).

Almost surely, 2^31297639 is an apocalyptic number.

31297639 is a deficient number, since it is larger than the sum of its proper divisors (1).

31297639 is an equidigital number, since it uses as much as digits as its factorization.

31297639 is an evil number, because the sum of its binary digits is even.

The product of its digits is 61236, while the sum is 40.

The square root of 31297639 is about 5594.4292827776. The cubic root of 31297639 is about 315.1402382201.

The spelling of 31297639 in words is "thirty-one million, two hundred ninety-seven thousand, six hundred thirty-nine".