31242257 has 4 divisors (see below), whose sum is σ = 32600640. Its totient is φ = 29883876.

The previous prime is 31242247. The next prime is 31242307. The reversal of 31242257 is 75224213.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 31242257 - 2¹⁰ = 31241233 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (31242217) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 679157 + ... + 679202.

It is an arithmetic number, because the mean of its divisors is an integer number (8150160).

Almost surely, 2^31242257 is an apocalyptic number.

It is an amenable number.

31242257 is a deficient number, since it is larger than the sum of its proper divisors (1358383).

31242257 is a wasteful number, since it uses less digits than its factorization.

31242257 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1358382.

The product of its digits is 3360, while the sum is 26.

The square root of 31242257 is about 5589.4773458705. The cubic root of 31242257 is about 314.9542454750.

The spelling of 31242257 in words is "thirty-one million, two hundred forty-two thousand, two hundred fifty-seven".