13121818191 has 12 divisors (see below), whose sum is σ = 19005387232. Its totient is φ = 8724040416.

The previous prime is 13121818183. The next prime is 13121818201. The reversal of 13121818191 is 19181812131.

13121818191 is a `hidden beast` number, since 1 + 312 + 181 + 81 + 91 = 666.

It is not a de Polignac number, because 13121818191 - 2³ = 13121818183 is a prime.

It is a super-3 number, since 3×13121818191³ (a number of 31 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (13121818141) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1983046 + ... + 1989651.

Almost surely, 2^13121818191 is an apocalyptic number.

13121818191 is a deficient number, since it is larger than the sum of its proper divisors (5883569041).

13121818191 is a wasteful number, since it uses less digits than its factorization.

13121818191 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3973070 (or 3973067 counting only the distinct ones).

The product of its digits is 3456, while the sum is 36.

The spelling of 13121818191 in words is "thirteen billion, one hundred twenty-one million, eight hundred eighteen thousand, one hundred ninety-one".