25720165255517 has 2 divisors, whose sum is σ = 25720165255518. Its totient is φ = 25720165255516.

The previous prime is 25720165255489. The next prime is 25720165255607. The reversal of 25720165255517 is 71555256102752.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 25708743203641 + 11422051876 = 5070379^2 + 106874^2 .

It is a cyclic number.

It is not a de Polignac number, because 25720165255517 - 2²⁸ = 25719896820061 is a prime.

It is a super-2 number, since 2×25720165255517² (a number of 28 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (25720164255517) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12860082627758 + 12860082627759.

It is an arithmetic number, because the mean of its divisors is an integer number (12860082627759).

Almost surely, 2^{25720165255517} is an apocalyptic number.

It is an amenable number.

25720165255517 is a deficient number, since it is larger than the sum of its proper divisors (1).

25720165255517 is an equidigital number, since it uses as much as digits as its factorization.

25720165255517 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 7350000, while the sum is 53.

The spelling of 25720165255517 in words is "twenty-five trillion, seven hundred twenty billion, one hundred sixty-five million, two hundred fifty-five thousand, five hundred seventeen".