21566254355 has 8 divisors (see below), whose sum is σ = 26068407552. Its totient is φ = 17127068608.

The previous prime is 21566254309. The next prime is 21566254373. The reversal of 21566254355 is 55345266512.

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

It is a cyclic number.

It is not a de Polignac number, because 21566254355 - 2²⁴ = 21549477139 is a prime.

It is a Duffinian number.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 15741107 + ... + 15742476.

It is an arithmetic number, because the mean of its divisors is an integer number (3258550944).

Almost surely, 2^21566254355 is an apocalyptic number.

21566254355 is a deficient number, since it is larger than the sum of its proper divisors (4502153197).

21566254355 is a wasteful number, since it uses less digits than its factorization.

21566254355 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31483725.

The product of its digits is 1080000, while the sum is 44.

The spelling of 21566254355 in words is "twenty-one billion, five hundred sixty-six million, two hundred fifty-four thousand, three hundred fifty-five".