15665623 has 2 divisors, whose sum is σ = 15665624. Its totient is φ = 15665622.

The previous prime is 15665609. The next prime is 15665641. The reversal of 15665623 is 32656651.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 15665623 - 2¹⁷ = 15534551 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (15665603) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 7832811 + 7832812.

It is an arithmetic number, because the mean of its divisors is an integer number (7832812).

Almost surely, 2^15665623 is an apocalyptic number.

15665623 is a deficient number, since it is larger than the sum of its proper divisors (1).

15665623 is an equidigital number, since it uses as much as digits as its factorization.

15665623 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 32400, while the sum is 34.

The square root of 15665623 is about 3957.9821879336. The cubic root of 15665623 is about 250.2164685114.

The spelling of 15665623 in words is "fifteen million, six hundred sixty-five thousand, six hundred twenty-three".