21264666055 has 4 divisors (see below), whose sum is σ = 25517599272. Its totient is φ = 17011732840.

The previous prime is 21264666001. The next prime is 21264666091. The reversal of 21264666055 is 55066646212.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 21264666055 - 2²⁷ = 21130448327 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 3 ways as a sum of consecutive naturals, for example, 2126466601 + ... + 2126466610.

It is an arithmetic number, because the mean of its divisors is an integer number (6379399818).

Almost surely, 2^21264666055 is an apocalyptic number.

21264666055 is a deficient number, since it is larger than the sum of its proper divisors (4252933217).

21264666055 is an equidigital number, since it uses as much as digits as its factorization.

21264666055 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4252933216.

The product of its (nonzero) digits is 518400, while the sum is 43.

The spelling of 21264666055 in words is "twenty-one billion, two hundred sixty-four million, six hundred sixty-six thousand, fifty-five".