13991939 has 4 divisors (see below), whose sum is σ = 15068256. Its totient is φ = 12915624.

The previous prime is 13991933. The next prime is 13991953. The reversal of 13991939 is 93919931.

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 13991939 - 2¹² = 13987843 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 13991939.

It is not an unprimeable number, because it can be changed into a prime (13991933) 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, 538139 + ... + 538164.

It is an arithmetic number, because the mean of its divisors is an integer number (3767064).

Almost surely, 2^13991939 is an apocalyptic number.

13991939 is a deficient number, since it is larger than the sum of its proper divisors (1076317).

13991939 is a wasteful number, since it uses less digits than its factorization.

13991939 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1076316.

The product of its digits is 59049, while the sum is 44.

The square root of 13991939 is about 3740.5800352352. The cubic root of 13991939 is about 240.9679600204.

The spelling of 13991939 in words is "thirteen million, nine hundred ninety-one thousand, nine hundred thirty-nine".