31279009 has 2 divisors, whose sum is σ = 31279010. Its totient is φ = 31279008.

The previous prime is 31279007. The next prime is 31279013. The reversal of 31279009 is 90097213.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 28654609 + 2624400 = 5353^2 + 1620^2 .

It is a cyclic number.

It is not a de Polignac number, because 31279009 - 2¹ = 31279007 is a prime.

Together with 31279007, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (31279007) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15639504 + 15639505.

It is an arithmetic number, because the mean of its divisors is an integer number (15639505).

Almost surely, 2^31279009 is an apocalyptic number.

It is an amenable number.

31279009 is a deficient number, since it is larger than the sum of its proper divisors (1).

31279009 is an equidigital number, since it uses as much as digits as its factorization.

31279009 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3402, while the sum is 31.

The square root of 31279009 is about 5592.7639857230. The cubic root of 31279009 is about 315.0776964636.

The spelling of 31279009 in words is "thirty-one million, two hundred seventy-nine thousand, nine".