15972661 has 2 divisors, whose sum is σ = 15972662. Its totient is φ = 15972660.

The previous prime is 15972659. The next prime is 15972689. The reversal of 15972661 is 16627951.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11350161 + 4622500 = 3369^2 + 2150^2 .

It is a cyclic number.

It is not a de Polignac number, because 15972661 - 2¹ = 15972659 is a prime.

Together with 15972659, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 15972661.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (15972611) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 7986330 + 7986331.

It is an arithmetic number, because the mean of its divisors is an integer number (7986331).

Almost surely, 2^15972661 is an apocalyptic number.

It is an amenable number.

15972661 is a deficient number, since it is larger than the sum of its proper divisors (1).

15972661 is an equidigital number, since it uses as much as digits as its factorization.

15972661 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 22680, while the sum is 37.

The square root of 15972661 is about 3996.5811639450. The cubic root of 15972661 is about 251.8406074007.

The spelling of 15972661 in words is "fifteen million, nine hundred seventy-two thousand, six hundred sixty-one".