15115661657 has 2 divisors, whose sum is σ = 15115661658. Its totient is φ = 15115661656.

The previous prime is 15115661599. The next prime is 15115661669. The reversal of 15115661657 is 75616651151.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 13486409161 + 1629252496 = 116131^2 + 40364^2 .

It is a cyclic number.

It is not a de Polignac number, because 15115661657 - 2¹⁴ = 15115645273 is a prime.

It is not a weakly prime, because it can be changed into another prime (15115661257) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 7557830828 + 7557830829.

It is an arithmetic number, because the mean of its divisors is an integer number (7557830829).

Almost surely, 2^15115661657 is an apocalyptic number.

It is an amenable number.

15115661657 is a deficient number, since it is larger than the sum of its proper divisors (1).

15115661657 is an equidigital number, since it uses as much as digits as its factorization.

15115661657 is an evil number, because the sum of its binary digits is even.

The product of its digits is 189000, while the sum is 44.

The spelling of 15115661657 in words is "fifteen billion, one hundred fifteen million, six hundred sixty-one thousand, six hundred fifty-seven".