21117872531464 has 8 divisors (see below), whose sum is σ = 39596010996510. Its totient is φ = 10558936265728.

The previous prime is 21117872531461. The next prime is 21117872531467. The reversal of 21117872531464 is 46413527871112.

It is an interprime number because it is at equal distance from previous prime (21117872531461) and next prime (21117872531467).

It can be written as a sum of positive squares in only one way, i.e., 20193717162564 + 924155368900 = 4493742^2 + 961330^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is not an unprimeable number, because it can be changed into a prime (21117872531461) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1319867033209 + ... + 1319867033224.

Almost surely, 2^{21117872531464} is an apocalyptic number.

It is an amenable number.

21117872531464 is a deficient number, since it is larger than the sum of its proper divisors (18478138465046).

21117872531464 is a wasteful number, since it uses less digits than its factorization.

21117872531464 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2639734066439 (or 2639734066435 counting only the distinct ones).

The product of its digits is 2257920, while the sum is 52.

The spelling of 21117872531464 in words is "twenty-one trillion, one hundred seventeen billion, eight hundred seventy-two million, five hundred thirty-one thousand, four hundred sixty-four".