21723345566 has 8 divisors (see below), whose sum is σ = 35091558264. Its totient is φ = 10026159480.

The previous prime is 21723345551. The next prime is 21723345571. The reversal of 21723345566 is 66554332712.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 417756620 + ... + 417756671.

It is an arithmetic number, because the mean of its divisors is an integer number (4386444783).

Almost surely, 2^21723345566 is an apocalyptic number.

21723345566 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

21723345566 is a deficient number, since it is larger than the sum of its proper divisors (13368212698).

21723345566 is a wasteful number, since it uses less digits than its factorization.

21723345566 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 835513306.

The product of its digits is 907200, while the sum is 44.

The spelling of 21723345566 in words is "twenty-one billion, seven hundred twenty-three million, three hundred forty-five thousand, five hundred sixty-six".