21874135491 has 24 divisors (see below), whose sum is σ = 35817301520. Its totient is φ = 12752531136.

The previous prime is 21874135373. The next prime is 21874135519. The reversal of 21874135491 is 19453147812.

21874135491 is a `hidden beast` number, since 2 + 187 + 413 + 54 + 9 + 1 = 666.

It is not a de Polignac number, because 21874135491 - 2⁹ = 21874134979 is a prime.

It is a super-2 number, since 2×21874135491² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21874135291) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 4917736 + ... + 4922181.

Almost surely, 2^21874135491 is an apocalyptic number.

21874135491 is a deficient number, since it is larger than the sum of its proper divisors (13943166029).

21874135491 is a wasteful number, since it uses less digits than its factorization.

21874135491 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9839955 (or 9839952 counting only the distinct ones).

The product of its digits is 241920, while the sum is 45.

The spelling of 21874135491 in words is "twenty-one billion, eight hundred seventy-four million, one hundred thirty-five thousand, four hundred ninety-one".