15665651 has 2 divisors, whose sum is σ = 15665652. Its totient is φ = 15665650.

The previous prime is 15665641. The next prime is 15665659. The reversal of 15665651 is 15656651.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 15665651 - 2¹⁴ = 15649267 is a prime.

It is a Sophie Germain prime.

It is not a weakly prime, because it can be changed into another prime (15665659) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 7832825 + 7832826.

It is an arithmetic number, because the mean of its divisors is an integer number (7832826).

Almost surely, 2^15665651 is an apocalyptic number.

15665651 is a deficient number, since it is larger than the sum of its proper divisors (1).

15665651 is an equidigital number, since it uses as much as digits as its factorization.

15665651 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 27000, while the sum is 35.

The square root of 15665651 is about 3957.9857250880. The cubic root of 15665651 is about 250.2166175864.

The spelling of 15665651 in words is "fifteen million, six hundred sixty-five thousand, six hundred fifty-one".