164518821 has 12 divisors (see below), whose sum is σ = 237919500. Its totient is φ = 109549440.

The previous prime is 164518787. The next prime is 164518897. The reversal of 164518821 is 128815461.

164518821 is a `hidden beast` number, since 1 + 64 + 518 + 82 + 1 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 14333796 + 150185025 = 3786^2 + 12255^2 .

It is not a de Polignac number, because 164518821 - 2¹⁰ = 164517797 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (164511821) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2446 + ... + 18303.

It is an arithmetic number, because the mean of its divisors is an integer number (19826625).

Almost surely, 2^164518821 is an apocalyptic number.

It is an amenable number.

164518821 is a deficient number, since it is larger than the sum of its proper divisors (73400679).

164518821 is a wasteful number, since it uses less digits than its factorization.

164518821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21636 (or 21633 counting only the distinct ones).

The product of its digits is 15360, while the sum is 36.

The square root of 164518821 is about 12826.4890363653. The cubic root of 164518821 is about 547.9469697117.

The spelling of 164518821 in words is "one hundred sixty-four million, five hundred eighteen thousand, eight hundred twenty-one".