2165256431309 has 2 divisors, whose sum is σ = 2165256431310. Its totient is φ = 2165256431308.

The previous prime is 2165256431297. The next prime is 2165256431321. The reversal of 2165256431309 is 9031346525612.

It is a balanced prime because it is at equal distance from previous prime (2165256431297) and next prime (2165256431321).

It can be written as a sum of positive squares in only one way, i.e., 1381682702500 + 783573728809 = 1175450^2 + 885197^2 .

It is a cyclic number.

It is not a de Polignac number, because 2165256431309 - 2²⁸ = 2164987995853 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2165256431329) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1082628215654 + 1082628215655.

It is an arithmetic number, because the mean of its divisors is an integer number (1082628215655).

Almost surely, 2^{2165256431309} is an apocalyptic number.

It is an amenable number.

2165256431309 is a deficient number, since it is larger than the sum of its proper divisors (1).

2165256431309 is an equidigital number, since it uses as much as digits as its factorization.

2165256431309 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1166400, while the sum is 47.

The spelling of 2165256431309 in words is "two trillion, one hundred sixty-five billion, two hundred fifty-six million, four hundred thirty-one thousand, three hundred nine".