21864464961 has 8 divisors (see below), whose sum is σ = 29273586144. Its totient is φ = 14515826880.

The previous prime is 21864464957. The next prime is 21864465031. The reversal of 21864464961 is 16946446812.

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

It is not a de Polignac number, because 21864464961 - 2² = 21864464957 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21864464561) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 15119931 + ... + 15121376.

It is an arithmetic number, because the mean of its divisors is an integer number (3659198268).

Almost surely, 2^21864464961 is an apocalyptic number.

It is an amenable number.

21864464961 is a deficient number, since it is larger than the sum of its proper divisors (7409121183).

21864464961 is a wasteful number, since it uses less digits than its factorization.

21864464961 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30241551.

The product of its digits is 1990656, while the sum is 51.

The spelling of 21864464961 in words is "twenty-one billion, eight hundred sixty-four million, four hundred sixty-four thousand, nine hundred sixty-one".