21555656327 has 4 divisors (see below), whose sum is σ = 22492858800. Its totient is φ = 20618453856.

The previous prime is 21555656323. The next prime is 21555656333. The reversal of 21555656327 is 72365655512.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 21555656327 - 2² = 21555656323 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21555656323) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 468601202 + ... + 468601247.

It is an arithmetic number, because the mean of its divisors is an integer number (5623214700).

Almost surely, 2^21555656327 is an apocalyptic number.

21555656327 is a deficient number, since it is larger than the sum of its proper divisors (937202473).

21555656327 is an equidigital number, since it uses as much as digits as its factorization.

21555656327 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 937202472.

The product of its digits is 1890000, while the sum is 47.

The spelling of 21555656327 in words is "twenty-one billion, five hundred fifty-five million, six hundred fifty-six thousand, three hundred twenty-seven".