21864635679 has 8 divisors (see below), whose sum is σ = 29157650352. Its totient is φ = 14574022400.

The previous prime is 21864635671. The next prime is 21864635693. The reversal of 21864635679 is 97653646812.

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 21864635679 - 2³ = 21864635671 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21864635671) 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, 578994 + ... + 615599.

It is an arithmetic number, because the mean of its divisors is an integer number (3644706294).

Almost surely, 2^21864635679 is an apocalyptic number.

21864635679 is a deficient number, since it is larger than the sum of its proper divisors (7293014673).

21864635679 is a wasteful number, since it uses less digits than its factorization.

21864635679 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1200697.

The product of its digits is 13063680, while the sum is 57.

The spelling of 21864635679 in words is "twenty-one billion, eight hundred sixty-four million, six hundred thirty-five thousand, six hundred seventy-nine".