21117584131 has 4 divisors (see below), whose sum is σ = 24134381872. Its totient is φ = 18100786392.

The previous prime is 21117584123. The next prime is 21117584171. The reversal of 21117584131 is 13148571112.

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

It is a cyclic number.

It is not a de Polignac number, because 21117584131 - 2³ = 21117584123 is a prime.

It is a super-2 number, since 2×21117584131² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21117584171) 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, 1508398860 + ... + 1508398873.

It is an arithmetic number, because the mean of its divisors is an integer number (6033595468).

Almost surely, 2^21117584131 is an apocalyptic number.

21117584131 is a deficient number, since it is larger than the sum of its proper divisors (3016797741).

21117584131 is an equidigital number, since it uses as much as digits as its factorization.

21117584131 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3016797740.

The product of its digits is 6720, while the sum is 34.

The spelling of 21117584131 in words is "twenty-one billion, one hundred seventeen million, five hundred eighty-four thousand, one hundred thirty-one".