13991816 has 16 divisors (see below), whose sum is σ = 27778140. Its totient is φ = 6584320.

The previous prime is 13991807. The next prime is 13991821. The reversal of 13991816 is 61819931.

It can be written as a sum of positive squares in 2 ways, for example, as 12180100 + 1811716 = 3490^2 + 1346^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 13991816.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 51305 + ... + 51576.

Almost surely, 2^13991816 is an apocalyptic number.

It is an amenable number.

13991816 is a deficient number, since it is larger than the sum of its proper divisors (13786324).

13991816 is a wasteful number, since it uses less digits than its factorization.

13991816 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 102904 (or 102900 counting only the distinct ones).

The product of its digits is 11664, while the sum is 38.

The square root of 13991816 is about 3740.5635938987. The cubic root of 13991816 is about 240.9672539199.

The spelling of 13991816 in words is "thirteen million, nine hundred ninety-one thousand, eight hundred sixteen".