31520897 has 2 divisors, whose sum is σ = 31520898. Its totient is φ = 31520896.

The previous prime is 31520861. The next prime is 31520899. The reversal of 31520897 is 79802513.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19749136 + 11771761 = 4444^2 + 3431^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-31520897 is a prime.

Together with 31520899, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (31520899) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15760448 + 15760449.

It is an arithmetic number, because the mean of its divisors is an integer number (15760449).

Almost surely, 2^31520897 is an apocalyptic number.

It is an amenable number.

31520897 is a deficient number, since it is larger than the sum of its proper divisors (1).

31520897 is an equidigital number, since it uses as much as digits as its factorization.

31520897 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 15120, while the sum is 35.

The square root of 31520897 is about 5614.3474242337. The cubic root of 31520897 is about 315.8878019936.

It can be divided in two parts, 315 and 20897, that added together give a palindrome (21212).

The spelling of 31520897 in words is "thirty-one million, five hundred twenty thousand, eight hundred ninety-seven".