21118664465 has 16 divisors (see below), whose sum is σ = 25532064000. Its totient is φ = 16768819392.

The previous prime is 21118664419. The next prime is 21118664543. The reversal of 21118664465 is 56446681112.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 21118664465 - 2¹⁰ = 21118663441 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 497756 + ... + 538514.

It is an arithmetic number, because the mean of its divisors is an integer number (1595754000).

Almost surely, 2^21118664465 is an apocalyptic number.

It is an amenable number.

21118664465 is a deficient number, since it is larger than the sum of its proper divisors (4413399535).

21118664465 is a wasteful number, since it uses less digits than its factorization.

21118664465 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 41536.

The product of its digits is 276480, while the sum is 44.

The spelling of 21118664465 in words is "twenty-one billion, one hundred eighteen million, six hundred sixty-four thousand, four hundred sixty-five".