2181921656255 has 16 divisors (see below), whose sum is σ = 2856744639648. Its totient is φ = 1586623872000.

The previous prime is 2181921656227. The next prime is 2181921656279. The reversal of 2181921656255 is 5526561291812.

It is not a de Polignac number, because 2181921656255 - 2⁶ = 2181921656191 is a prime.

It is a super-2 number, since 2×2181921656255² (a number of 25 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 = 2181921656197 and 2181921656206.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2466686 + ... + 3232395.

It is an arithmetic number, because the mean of its divisors is an integer number (178546539978).

Almost surely, 2^{2181921656255} is an apocalyptic number.

2181921656255 is a deficient number, since it is larger than the sum of its proper divisors (674822983393).

2181921656255 is a wasteful number, since it uses less digits than its factorization.

2181921656255 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5706058.

The product of its digits is 2592000, while the sum is 53.

The spelling of 2181921656255 in words is "two trillion, one hundred eighty-one billion, nine hundred twenty-one million, six hundred fifty-six thousand, two hundred fifty-five".