21612668255 has 8 divisors (see below), whose sum is σ = 25936041552. Its totient is φ = 17289574848.

The previous prime is 21612668251. The next prime is 21612668281. The reversal of 21612668255 is 55286621612.

It is a happy number.

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 21612668255 - 2² = 21612668251 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 (21612668251) by changing a digit.

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, 183179 + ... + 277091.

It is an arithmetic number, because the mean of its divisors is an integer number (3242005194).

Almost surely, 2^21612668255 is an apocalyptic number.

21612668255 is a deficient number, since it is larger than the sum of its proper divisors (4323373297).

21612668255 is an equidigital number, since it uses as much as digits as its factorization.

21612668255 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 139945.

The product of its digits is 345600, while the sum is 44.

The spelling of 21612668255 in words is "twenty-one billion, six hundred twelve million, six hundred sixty-eight thousand, two hundred fifty-five".