13991997 has 16 divisors (see below), whose sum is σ = 19121792. Its totient is φ = 9097920.

The previous prime is 13991987. The next prime is 13992019. The reversal of 13991997 is 79919931.

It is not a de Polignac number, because 13991997 - 2⁶ = 13991933 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (13991977) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 28488 + ... + 28974.

It is an arithmetic number, because the mean of its divisors is an integer number (1195112).

Almost surely, 2^13991997 is an apocalyptic number.

It is an amenable number.

13991997 is a deficient number, since it is larger than the sum of its proper divisors (5129795).

13991997 is a wasteful number, since it uses less digits than its factorization.

13991997 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 708.

The product of its digits is 137781, while the sum is 48.

The square root of 13991997 is about 3740.5877880355. The cubic root of 13991997 is about 240.9682929769.

The spelling of 13991997 in words is "thirteen million, nine hundred ninety-one thousand, nine hundred ninety-seven".