15957691 has 2 divisors, whose sum is σ = 15957692. Its totient is φ = 15957690.

The previous prime is 15957649. The next prime is 15957703. The reversal of 15957691 is 19675951.

It is a strong prime.

It is an emirp because it is prime and its reverse (19675951) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 15957691 - 2⁷ = 15957563 is a prime.

It is not a weakly prime, because it can be changed into another prime (15957391) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 7978845 + 7978846.

It is an arithmetic number, because the mean of its divisors is an integer number (7978846).

Almost surely, 2^15957691 is an apocalyptic number.

15957691 is a deficient number, since it is larger than the sum of its proper divisors (1).

15957691 is an equidigital number, since it uses as much as digits as its factorization.

15957691 is an evil number, because the sum of its binary digits is even.

The product of its digits is 85050, while the sum is 43.

The square root of 15957691 is about 3994.7078741755. The cubic root of 15957691 is about 251.7619055842.

The spelling of 15957691 in words is "fifteen million, nine hundred fifty-seven thousand, six hundred ninety-one".