21766663091 has 8 divisors (see below), whose sum is σ = 22068938304. Its totient is φ = 21464498880.

The previous prime is 21766663073. The next prime is 21766663097. The reversal of 21766663091 is 19036666712.

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 21766663091 - 2⁶ = 21766663027 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21766663097) 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, 416006 + ... + 465396.

It is an arithmetic number, because the mean of its divisors is an integer number (2758617288).

Almost surely, 2^21766663091 is an apocalyptic number.

21766663091 is a deficient number, since it is larger than the sum of its proper divisors (302275213).

21766663091 is an equidigital number, since it uses as much as digits as its factorization.

21766663091 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 55501.

The product of its (nonzero) digits is 489888, while the sum is 47.

The spelling of 21766663091 in words is "twenty-one billion, seven hundred sixty-six million, six hundred sixty-three thousand, ninety-one".