13891978 has 8 divisors (see below), whose sum is σ = 21281472. Its totient is φ = 6798156.

The previous prime is 13891961. The next prime is 13891979. The reversal of 13891978 is 87919831.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not an unprimeable number, because it can be changed into a prime (13891979) 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, 73800 + ... + 73987.

It is an arithmetic number, because the mean of its divisors is an integer number (2660184).

Almost surely, 2^13891978 is an apocalyptic number.

13891978 is a deficient number, since it is larger than the sum of its proper divisors (7389494).

13891978 is a wasteful number, since it uses less digits than its factorization.

13891978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 147836.

The product of its digits is 108864, while the sum is 46.

The square root of 13891978 is about 3727.1943872033. The cubic root of 13891978 is about 240.3927481402.

The spelling of 13891978 in words is "thirteen million, eight hundred ninety-one thousand, nine hundred seventy-eight".