2171321318655 has 24 divisors (see below), whose sum is σ = 3786713347248. Its totient is φ = 1150933504896.

The previous prime is 2171321318641. The next prime is 2171321318671. The reversal of 2171321318655 is 5568131231712.

2171321318655 is a `hidden beast` number, since 2 + 1 + 7 + 1 + 321 + 318 + 6 + 5 + 5 = 666.

It is not a de Polignac number, because 2171321318655 - 2²² = 2171317124351 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a self number, because there is not a number n which added to its sum of digits gives 2171321318655.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 148003662 + ... + 148018331.

It is an arithmetic number, because the mean of its divisors is an integer number (157779722802).

Almost surely, 2^{2171321318655} is an apocalyptic number.

2171321318655 is a deficient number, since it is larger than the sum of its proper divisors (1615392028593).

2171321318655 is a wasteful number, since it uses less digits than its factorization.

2171321318655 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 296022167 (or 296022164 counting only the distinct ones).

The product of its digits is 302400, while the sum is 45.

The spelling of 2171321318655 in words is "two trillion, one hundred seventy-one billion, three hundred twenty-one million, three hundred eighteen thousand, six hundred fifty-five".