31195394509 has 2 divisors, whose sum is σ = 31195394510. Its totient is φ = 31195394508.

The previous prime is 31195394507. The next prime is 31195394533. The reversal of 31195394509 is 90549359113.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 30283656484 + 911738025 = 174022^2 + 30195^2 .

It is a cyclic number.

It is not a de Polignac number, because 31195394509 - 2¹ = 31195394507 is a prime.

Together with 31195394507, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31195394507) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15597697254 + 15597697255.

It is an arithmetic number, because the mean of its divisors is an integer number (15597697255).

Almost surely, 2^31195394509 is an apocalyptic number.

It is an amenable number.

31195394509 is a deficient number, since it is larger than the sum of its proper divisors (1).

31195394509 is an equidigital number, since it uses as much as digits as its factorization.

31195394509 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 656100, while the sum is 49.

The spelling of 31195394509 in words is "thirty-one billion, one hundred ninety-five million, three hundred ninety-four thousand, five hundred nine".