21472320665 has 8 divisors (see below), whose sum is σ = 25785211200. Its totient is φ = 17165572272.

The previous prime is 21472320659. The next prime is 21472320719. The reversal of 21472320665 is 56602327412.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21472320665 - 2²⁰ = 21471272089 is a prime.

It is a super-2 number, since 2×21472320665² (a number of 21 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1527839 + ... + 1541828.

It is an arithmetic number, because the mean of its divisors is an integer number (3223151400).

Almost surely, 2^21472320665 is an apocalyptic number.

It is an amenable number.

21472320665 is a deficient number, since it is larger than the sum of its proper divisors (4312890535).

21472320665 is a wasteful number, since it uses less digits than its factorization.

21472320665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3071071.

The product of its (nonzero) digits is 120960, while the sum is 38.

The spelling of 21472320665 in words is "twenty-one billion, four hundred seventy-two million, three hundred twenty thousand, six hundred sixty-five".