164621 has 2 divisors, whose sum is σ = 164622. Its totient is φ = 164620.

The previous prime is 164617. The next prime is 164623. The reversal of 164621 is 126461.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 148996 + 15625 = 386^2 + 125^2 .

It is an emirp because it is prime and its reverse (126461) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 164621 - 2² = 164617 is a prime.

It is a Sophie Germain prime.

Together with 164623, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is equal to p₁₅₀₆₈ and since 164621 and 15068 have the same sum of digits, it is a Honaker prime.

It is a junction number, because it is equal to n+sod(n) for n = 164593 and 164602.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (164623) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 82310 + 82311.

It is an arithmetic number, because the mean of its divisors is an integer number (82311).

2¹⁶⁴⁶²¹ is an apocalyptic number.

It is an amenable number.

164621 is a deficient number, since it is larger than the sum of its proper divisors (1).

164621 is an equidigital number, since it uses as much as digits as its factorization.

164621 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 288, while the sum is 20.

The square root of 164621 is about 405.7351352792. The cubic root of 164621 is about 54.8060385482.

The spelling of 164621 in words is "one hundred sixty-four thousand, six hundred twenty-one".