16391431709 has 2 divisors, whose sum is σ = 16391431710. Its totient is φ = 16391431708.

The previous prime is 16391431673. The next prime is 16391431733. The reversal of 16391431709 is 90713419361.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 9437539609 + 6953892100 = 97147^2 + 83390^2 .

It is a cyclic number.

It is not a de Polignac number, because 16391431709 - 2⁸ = 16391431453 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 16391431709.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (16391431789) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8195715854 + 8195715855.

It is an arithmetic number, because the mean of its divisors is an integer number (8195715855).

Almost surely, 2^16391431709 is an apocalyptic number.

It is an amenable number.

16391431709 is a deficient number, since it is larger than the sum of its proper divisors (1).

16391431709 is an equidigital number, since it uses as much as digits as its factorization.

16391431709 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 122472, while the sum is 44.

The spelling of 16391431709 in words is "sixteen billion, three hundred ninety-one million, four hundred thirty-one thousand, seven hundred nine".