21659444523 has 8 divisors (see below), whose sum is σ = 32088066000. Its totient is φ = 14439629664.

The previous prime is 21659444509. The next prime is 21659444531. The reversal of 21659444523 is 32544495612.

21659444523 is a `hidden beast` number, since 2 + 1 + 6 + 594 + 4 + 4 + 52 + 3 = 666.

It is not a de Polignac number, because 21659444523 - 2⁸ = 21659444267 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21659444533) 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, 401100798 + ... + 401100851.

It is an arithmetic number, because the mean of its divisors is an integer number (4011008250).

Almost surely, 2^21659444523 is an apocalyptic number.

21659444523 is a deficient number, since it is larger than the sum of its proper divisors (10428621477).

21659444523 is an equidigital number, since it uses as much as digits as its factorization.

21659444523 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 802201658 (or 802201652 counting only the distinct ones).

The product of its digits is 1036800, while the sum is 45.

The spelling of 21659444523 in words is "twenty-one billion, six hundred fifty-nine million, four hundred forty-four thousand, five hundred twenty-three".