164221721055 has 120 divisors (see below), whose sum is σ = 343819864080. Its totient is φ = 74771424000.

The previous prime is 164221721017. The next prime is 164221721057. The reversal of 164221721055 is 550127122461.

164221721055 is a `hidden beast` number, since 1 + 6 + 422 + 17 + 210 + 5 + 5 = 666.

It is not a de Polignac number, because 164221721055 - 2²⁰ = 164220672479 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (164221721057) by changing a digit.

It is a polite number, since it can be written in 119 ways as a sum of consecutive naturals, for example, 4964611 + ... + 4997579.

It is an arithmetic number, because the mean of its divisors is an integer number (2865165534).

Almost surely, 2^164221721055 is an apocalyptic number.

164221721055 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

164221721055 is an abundant number, since it is smaller than the sum of its proper divisors (179598143025).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

164221721055 is a wasteful number, since it uses less digits than its factorization.

164221721055 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33251 (or 33235 counting only the distinct ones).

The product of its (nonzero) digits is 33600, while the sum is 36.

The spelling of 164221721055 in words is "one hundred sixty-four billion, two hundred twenty-one million, seven hundred twenty-one thousand, fifty-five".