31109809 has 2 divisors, whose sum is σ = 31109810. Its totient is φ = 31109808.

The previous prime is 31109803. The next prime is 31109839. The reversal of 31109809 is 90890113.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 29669809 + 1440000 = 5447^2 + 1200^2 .

It is a cyclic number.

It is not a de Polignac number, because 31109809 - 2³ = 31109801 is a prime.

It is not a weakly prime, because it can be changed into another prime (31109801) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15554904 + 15554905.

It is an arithmetic number, because the mean of its divisors is an integer number (15554905).

Almost surely, 2^31109809 is an apocalyptic number.

It is an amenable number.

31109809 is a deficient number, since it is larger than the sum of its proper divisors (1).

31109809 is an equidigital number, since it uses as much as digits as its factorization.

31109809 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1944, while the sum is 31.

The square root of 31109809 is about 5577.6167849719. The cubic root of 31109809 is about 314.5085441301.

The spelling of 31109809 in words is "thirty-one million, one hundred nine thousand, eight hundred nine".