425664523415581 has 2 divisors, whose sum is σ = 425664523415582. Its totient is φ = 425664523415580.

The previous prime is 425664523415569. The next prime is 425664523415597. The reversal of 425664523415581 is 185514325466524.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 315352459683556 + 110312063732025 = 17758166^2 + 10502955^2 .

It is a cyclic number.

It is not a de Polignac number, because 425664523415581 - 2¹¹ = 425664523413533 is a prime.

It is a super-2 number, since 2×425664523415581² (a number of 30 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (425664523415501) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 212832261707790 + 212832261707791.

It is an arithmetic number, because the mean of its divisors is an integer number (212832261707791).

Almost surely, 2^{425664523415581} is an apocalyptic number.

It is an amenable number.

425664523415581 is a deficient number, since it is larger than the sum of its proper divisors (1).

425664523415581 is an equidigital number, since it uses as much as digits as its factorization.

425664523415581 is an evil number, because the sum of its binary digits is even.

The product of its digits is 138240000, while the sum is 61.

The spelling of 425664523415581 in words is "four hundred twenty-five trillion, six hundred sixty-four billion, five hundred twenty-three million, four hundred fifteen thousand, five hundred eighty-one".