31312409 has 2 divisors, whose sum is σ = 31312410. Its totient is φ = 31312408.

The previous prime is 31312403. The next prime is 31312423. The reversal of 31312409 is 90421313.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 31047184 + 265225 = 5572^2 + 515^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-31312409 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (31312403) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15656204 + 15656205.

It is an arithmetic number, because the mean of its divisors is an integer number (15656205).

Almost surely, 2^31312409 is an apocalyptic number.

It is an amenable number.

31312409 is a deficient number, since it is larger than the sum of its proper divisors (1).

31312409 is an equidigital number, since it uses as much as digits as its factorization.

31312409 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 648, while the sum is 23.

The square root of 31312409 is about 5595.7491902336. The cubic root of 31312409 is about 315.1898041453.

The spelling of 31312409 in words is "thirty-one million, three hundred twelve thousand, four hundred nine".