31312999 has 2 divisors, whose sum is σ = 31313000. Its totient is φ = 31312998.

The previous prime is 31312973. The next prime is 31313017. The reversal of 31312999 is 99921313.

It is a strong prime.

It is an emirp because it is prime and its reverse (99921313) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 31312999 - 2⁷ = 31312871 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31312909) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15656499 + 15656500.

It is an arithmetic number, because the mean of its divisors is an integer number (15656500).

Almost surely, 2^31312999 is an apocalyptic number.

31312999 is a deficient number, since it is larger than the sum of its proper divisors (1).

31312999 is an equidigital number, since it uses as much as digits as its factorization.

31312999 is an evil number, because the sum of its binary digits is even.

The product of its digits is 13122, while the sum is 37.

The square root of 31312999 is about 5595.8019085740. The cubic root of 31312999 is about 315.1917837739.

The spelling of 31312999 in words is "thirty-one million, three hundred twelve thousand, nine hundred ninety-nine".