15561697 has 2 divisors, whose sum is σ = 15561698. Its totient is φ = 15561696.

The previous prime is 15561677. The next prime is 15561737. The reversal of 15561697 is 79616551.

It is an a-pointer prime, because the next prime (15561737) can be obtained adding 15561697 to its sum of digits (40).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15555136 + 6561 = 3944^2 + 81^2 .

It is a cyclic number.

It is not a de Polignac number, because 15561697 - 2¹⁹ = 15037409 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (15561617) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 7780848 + 7780849.

It is an arithmetic number, because the mean of its divisors is an integer number (7780849).

Almost surely, 2^15561697 is an apocalyptic number.

It is an amenable number.

15561697 is a deficient number, since it is larger than the sum of its proper divisors (1).

15561697 is an equidigital number, since it uses as much as digits as its factorization.

15561697 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 56700, while the sum is 40.

The square root of 15561697 is about 3944.8316820873. The cubic root of 15561697 is about 249.6619270328.

The spelling of 15561697 in words is "fifteen million, five hundred sixty-one thousand, six hundred ninety-seven".