31299809 has 2 divisors, whose sum is σ = 31299810. Its totient is φ = 31299808.

The previous prime is 31299781. The next prime is 31299847. The reversal of 31299809 is 90899213.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 31192225 + 107584 = 5585^2 + 328^2 .

It is an emirp because it is prime and its reverse (90899213) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-31299809 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (31299899) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15649904 + 15649905.

It is an arithmetic number, because the mean of its divisors is an integer number (15649905).

Almost surely, 2^31299809 is an apocalyptic number.

It is an amenable number.

31299809 is a deficient number, since it is larger than the sum of its proper divisors (1).

31299809 is an equidigital number, since it uses as much as digits as its factorization.

31299809 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 34992, while the sum is 41.

The square root of 31299809 is about 5594.6232223448. The cubic root of 31299809 is about 315.1475213947.

The spelling of 31299809 in words is "thirty-one million, two hundred ninety-nine thousand, eight hundred nine".