31857997 has 2 divisors, whose sum is σ = 31857998. Its totient is φ = 31857996.

The previous prime is 31857989. The next prime is 31858039. The reversal of 31857997 is 79975813.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21288996 + 10569001 = 4614^2 + 3251^2 .

It is an emirp because it is prime and its reverse (79975813) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 31857997 - 2³ = 31857989 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 31857997.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31857937) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15928998 + 15928999.

It is an arithmetic number, because the mean of its divisors is an integer number (15928999).

Almost surely, 2^31857997 is an apocalyptic number.

It is an amenable number.

31857997 is a deficient number, since it is larger than the sum of its proper divisors (1).

31857997 is an equidigital number, since it uses as much as digits as its factorization.

31857997 is an evil number, because the sum of its binary digits is even.

The product of its digits is 476280, while the sum is 49.

The square root of 31857997 is about 5644.2888834644. The cubic root of 31857997 is about 317.0098979551.

The spelling of 31857997 in words is "thirty-one million, eight hundred fifty-seven thousand, nine hundred ninety-seven".