31315901 has 2 divisors, whose sum is σ = 31315902. Its totient is φ = 31315900.

The previous prime is 31315897. The next prime is 31315913. The reversal of 31315901 is 10951313.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 26275876 + 5040025 = 5126^2 + 2245^2 .

It is an emirp because it is prime and its reverse (10951313) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 31315901 - 2² = 31315897 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31315981) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15657950 + 15657951.

It is an arithmetic number, because the mean of its divisors is an integer number (15657951).

Almost surely, 2^31315901 is an apocalyptic number.

It is an amenable number.

31315901 is a deficient number, since it is larger than the sum of its proper divisors (1).

31315901 is an equidigital number, since it uses as much as digits as its factorization.

31315901 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 405, while the sum is 23.

The square root of 31315901 is about 5596.0612040970. The cubic root of 31315901 is about 315.2015205002.

The spelling of 31315901 in words is "thirty-one million, three hundred fifteen thousand, nine hundred one".