21721739255 has 8 divisors (see below), whose sum is σ = 26620684992. Its totient is φ = 17007659488.

The previous prime is 21721739233. The next prime is 21721739269. The reversal of 21721739255 is 55293712712.

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 21721739255 - 2⁶ = 21721739191 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, 46216232 + ... + 46216701.

It is an arithmetic number, because the mean of its divisors is an integer number (3327585624).

Almost surely, 2^21721739255 is an apocalyptic number.

21721739255 is a deficient number, since it is larger than the sum of its proper divisors (4898945737).

21721739255 is an equidigital number, since it uses as much as digits as its factorization.

21721739255 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 92432985.

The product of its digits is 264600, while the sum is 44.

The spelling of 21721739255 in words is "twenty-one billion, seven hundred twenty-one million, seven hundred thirty-nine thousand, two hundred fifty-five".