13915991 has 4 divisors (see below), whose sum is σ = 14144184. Its totient is φ = 13687800.

The previous prime is 13915981. The next prime is 13916011. The reversal of 13915991 is 19951931.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 13915991 - 2⁶ = 13915927 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (13915981) 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, 114005 + ... + 114126.

It is an arithmetic number, because the mean of its divisors is an integer number (3536046).

Almost surely, 2^13915991 is an apocalyptic number.

13915991 is a deficient number, since it is larger than the sum of its proper divisors (228193).

13915991 is an equidigital number, since it uses as much as digits as its factorization.

13915991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 228192.

The product of its digits is 10935, while the sum is 38.

The square root of 13915991 is about 3730.4143201527. The cubic root of 13915991 is about 240.5311788278.

The spelling of 13915991 in words is "thirteen million, nine hundred fifteen thousand, nine hundred ninety-one".