21660551155255 has 8 divisors (see below), whose sum is σ = 26093800148112. Its totient is φ = 17261015083008.

The previous prime is 21660551155219. The next prime is 21660551155273. The reversal of 21660551155255 is 55255115506612.

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 21660551155255 - 2²⁹ = 21660014284343 is a prime.

It is a super-2 number, since 2×21660551155255² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21660551155199 and 21660551155208.

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, 8428228737 + ... + 8428231306.

It is an arithmetic number, because the mean of its divisors is an integer number (3261725018514).

Almost surely, 2^{21660551155255} is an apocalyptic number.

21660551155255 is a deficient number, since it is larger than the sum of its proper divisors (4433248992857).

21660551155255 is a wasteful number, since it uses less digits than its factorization.

21660551155255 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16856460305.

The product of its (nonzero) digits is 2250000, while the sum is 49.

The spelling of 21660551155255 in words is "twenty-one trillion, six hundred sixty billion, five hundred fifty-one million, one hundred fifty-five thousand, two hundred fifty-five".