15631325581 has 2 divisors, whose sum is σ = 15631325582. Its totient is φ = 15631325580.

The previous prime is 15631325569. The next prime is 15631325617. The reversal of 15631325581 is 18552313651.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 10066911556 + 5564414025 = 100334^2 + 74595^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-15631325581 is a prime.

It is a super-2 number, since 2×15631325581² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (15631325561) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 7815662790 + 7815662791.

It is an arithmetic number, because the mean of its divisors is an integer number (7815662791).

Almost surely, 2^15631325581 is an apocalyptic number.

It is an amenable number.

15631325581 is a deficient number, since it is larger than the sum of its proper divisors (1).

15631325581 is an equidigital number, since it uses as much as digits as its factorization.

15631325581 is an evil number, because the sum of its binary digits is even.

The product of its digits is 108000, while the sum is 40.

The spelling of 15631325581 in words is "fifteen billion, six hundred thirty-one million, three hundred twenty-five thousand, five hundred eighty-one".