509256321391 has 2 divisors, whose sum is σ = 509256321392. Its totient is φ = 509256321390.

The previous prime is 509256321359. The next prime is 509256321419. The reversal of 509256321391 is 193123652905.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 509256321391 - 2⁵ = 509256321359 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (509256321311) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 254628160695 + 254628160696.

It is an arithmetic number, because the mean of its divisors is an integer number (254628160696).

Almost surely, 2^509256321391 is an apocalyptic number.

509256321391 is a deficient number, since it is larger than the sum of its proper divisors (1).

509256321391 is an equidigital number, since it uses as much as digits as its factorization.

509256321391 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 437400, while the sum is 46.

The spelling of 509256321391 in words is "five hundred nine billion, two hundred fifty-six million, three hundred twenty-one thousand, three hundred ninety-one".