31897949 has 2 divisors, whose sum is σ = 31897950. Its totient is φ = 31897948.

The previous prime is 31897927. The next prime is 31897951. The reversal of 31897949 is 94979813.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 27825625 + 4072324 = 5275^2 + 2018^2 .

It is an emirp because it is prime and its reverse (94979813) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 31897949 - 2²⁴ = 15120733 is a prime.

It is a Sophie Germain prime.

Together with 31897951, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 31897897 and 31897906.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31897919) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15948974 + 15948975.

It is an arithmetic number, because the mean of its divisors is an integer number (15948975).

Almost surely, 2^31897949 is an apocalyptic number.

It is an amenable number.

31897949 is a deficient number, since it is larger than the sum of its proper divisors (1).

31897949 is an equidigital number, since it uses as much as digits as its factorization.

31897949 is an evil number, because the sum of its binary digits is even.

The product of its digits is 489888, while the sum is 50.

The square root of 31897949 is about 5647.8269272349. The cubic root of 31897949 is about 317.1423596079.

The spelling of 31897949 in words is "thirty-one million, eight hundred ninety-seven thousand, nine hundred forty-nine".