21664464446 has 8 divisors (see below), whose sum is σ = 32501219880. Its totient is φ = 10830724488.

The previous prime is 21664464443. The next prime is 21664464473. The reversal of 21664464446 is 64446446612.

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

It is a self number, because there is not a number n which added to its sum of digits gives 21664464446.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21664464443) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 735821 + ... + 764696.

It is an arithmetic number, because the mean of its divisors is an integer number (4062652485).

Almost surely, 2^21664464446 is an apocalyptic number.

21664464446 is a deficient number, since it is larger than the sum of its proper divisors (10836755434).

21664464446 is a wasteful number, since it uses less digits than its factorization.

21664464446 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1507738.

The product of its digits is 2654208, while the sum is 47.

The spelling of 21664464446 in words is "twenty-one billion, six hundred sixty-four million, four hundred sixty-four thousand, four hundred forty-six".