21065564223 has 48 divisors (see below), whose sum is σ = 33605095680. Its totient is φ = 12609648000.

The previous prime is 21065564183. The next prime is 21065564227. The reversal of 21065564223 is 32246556012.

21065564223 is a `hidden beast` number, since 2 + 1 + 0 + 6 + 5 + 5 + 642 + 2 + 3 = 666.

It is not a de Polignac number, because 21065564223 - 2¹² = 21065560127 is a prime.

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21065564227) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 4168048 + ... + 4173098.

It is an arithmetic number, because the mean of its divisors is an integer number (700106160).

Almost surely, 2^21065564223 is an apocalyptic number.

21065564223 is a deficient number, since it is larger than the sum of its proper divisors (12539531457).

21065564223 is a wasteful number, since it uses less digits than its factorization.

21065564223 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5580 (or 5577 counting only the distinct ones).

The product of its (nonzero) digits is 86400, while the sum is 36.

The spelling of 21065564223 in words is "twenty-one billion, sixty-five million, five hundred sixty-four thousand, two hundred twenty-three".