21166645255 has 8 divisors (see below), whose sum is σ = 29028542112. Its totient is φ = 14514271008.

The previous prime is 21166645249. The next prime is 21166645261. The reversal of 21166645255 is 55254666112.

It is an interprime number because it is at equal distance from previous prime (21166645249) and next prime (21166645261).

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21166645255 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 302380612 + ... + 302380681.

It is an arithmetic number, because the mean of its divisors is an integer number (3628567764).

Almost surely, 2^21166645255 is an apocalyptic number.

21166645255 is a deficient number, since it is larger than the sum of its proper divisors (7861896857).

21166645255 is an equidigital number, since it uses as much as digits as its factorization.

21166645255 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 604761305.

The product of its digits is 432000, while the sum is 43.

The spelling of 21166645255 in words is "twenty-one billion, one hundred sixty-six million, six hundred forty-five thousand, two hundred fifty-five".