21667521863 has 32 divisors (see below), whose sum is σ = 24614150400. Its totient is φ = 18935562240.

The previous prime is 21667521859. The next prime is 21667521881. The reversal of 21667521863 is 36812576612.

It is a cyclic number.

It is not a de Polignac number, because 21667521863 - 2² = 21667521859 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21667521833) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 8853506 + ... + 8855952.

It is an arithmetic number, because the mean of its divisors is an integer number (769192200).

Almost surely, 2^21667521863 is an apocalyptic number.

21667521863 is a deficient number, since it is larger than the sum of its proper divisors (2946628537).

21667521863 is a wasteful number, since it uses less digits than its factorization.

21667521863 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2987.

The product of its digits is 725760, while the sum is 47.

The spelling of 21667521863 in words is "twenty-one billion, six hundred sixty-seven million, five hundred twenty-one thousand, eight hundred sixty-three".