13991988 has 24 divisors (see below), whose sum is σ = 33445440. Its totient is φ = 4550080.

The previous prime is 13991987. The next prime is 13992019. The reversal of 13991988 is 88919931.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (13991987) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 13728 + ... + 14711.

It is an arithmetic number, because the mean of its divisors is an integer number (1393560).

Almost surely, 2^13991988 is an apocalyptic number.

It is an amenable number.

13991988 is an abundant number, since it is smaller than the sum of its proper divisors (19453452).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

13991988 is a wasteful number, since it uses less digits than its factorization.

13991988 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28487 (or 28485 counting only the distinct ones).

The product of its digits is 139968, while the sum is 48.

The square root of 13991988 is about 3740.5865850158. The cubic root of 13991988 is about 240.9682413113.

The spelling of 13991988 in words is "thirteen million, nine hundred ninety-one thousand, nine hundred eighty-eight".