13991657 has 4 divisors (see below), whose sum is σ = 14728080. Its totient is φ = 13255236.

The previous prime is 13991651. The next prime is 13991687. The reversal of 13991657 is 75619931.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 75619931 = 61 ⋅1239671.

It is not a de Polignac number, because 13991657 - 2⁸ = 13991401 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (13991651) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 368183 + ... + 368220.

It is an arithmetic number, because the mean of its divisors is an integer number (3682020).

Almost surely, 2^13991657 is an apocalyptic number.

It is an amenable number.

13991657 is a deficient number, since it is larger than the sum of its proper divisors (736423).

13991657 is an equidigital number, since it uses as much as digits as its factorization.

13991657 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 736422.

The product of its digits is 51030, while the sum is 41.

The square root of 13991657 is about 3740.5423403565. The cubic root of 13991657 is about 240.9663411496.

The spelling of 13991657 in words is "thirteen million, nine hundred ninety-one thousand, six hundred fifty-seven".