13971931668 has 36 divisors (see below), whose sum is σ = 35321662740. Its totient is φ = 4656819456.

The previous prime is 13971931643. The next prime is 13971931697. The reversal of 13971931668 is 86613917931.

It is a happy number.

13971931668 is a `hidden beast` number, since 1 + 397 + 1 + 93 + 166 + 8 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 6617497104 + 7354434564 = 81348^2 + 85758^2 .

It is a tau number, because it is divible by the number of its divisors (36).

It is a super-2 number, since 2×13971931668² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 524446 + ... + 550442.

Almost surely, 2^13971931668 is an apocalyptic number.

13971931668 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is an amenable number.

13971931668 is an abundant number, since it is smaller than the sum of its proper divisors (21349731072).

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

13971931668 is a wasteful number, since it uses less digits than its factorization.

13971931668 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40936 (or 40931 counting only the distinct ones).

The product of its digits is 1469664, while the sum is 54.

The spelling of 13971931668 in words is "thirteen billion, nine hundred seventy-one million, nine hundred thirty-one thousand, six hundred sixty-eight".