13891971 has 4 divisors (see below), whose sum is σ = 18522632. Its totient is φ = 9261312.

The previous prime is 13891961. The next prime is 13891979. The reversal of 13891971 is 17919831.

13891971 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 13891971 - 2¹⁷ = 13760899 is a prime.

It is a Duffinian number.

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, 2315326 + ... + 2315331.

It is an arithmetic number, because the mean of its divisors is an integer number (4630658).

Almost surely, 2^13891971 is an apocalyptic number.

13891971 is a deficient number, since it is larger than the sum of its proper divisors (4630661).

13891971 is an equidigital number, since it uses as much as digits as its factorization.

13891971 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4630660.

The product of its digits is 13608, while the sum is 39.

The square root of 13891971 is about 3727.1934481591. The cubic root of 13891971 is about 240.3927077632.

The spelling of 13891971 in words is "thirteen million, eight hundred ninety-one thousand, nine hundred seventy-one".