164188021 has 2 divisors, whose sum is σ = 164188022. Its totient is φ = 164188020.

The previous prime is 164187979. The next prime is 164188043. The reversal of 164188021 is 120881461.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 154107396 + 10080625 = 12414^2 + 3175^2 .

It is an emirp because it is prime and its reverse (120881461) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 164188021 - 2¹⁵ = 164155253 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (164188081) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 82094010 + 82094011.

It is an arithmetic number, because the mean of its divisors is an integer number (82094011).

Almost surely, 2^164188021 is an apocalyptic number.

It is an amenable number.

164188021 is a deficient number, since it is larger than the sum of its proper divisors (1).

164188021 is an equidigital number, since it uses as much as digits as its factorization.

164188021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3072, while the sum is 31.

The square root of 164188021 is about 12813.5873587376. The cubic root of 164188021 is about 547.5794687368.

The spelling of 164188021 in words is "one hundred sixty-four million, one hundred eighty-eight thousand, twenty-one".