164965621 has 2 divisors, whose sum is σ = 164965622. Its totient is φ = 164965620.

The previous prime is 164965613. The next prime is 164965643. The reversal of 164965621 is 126569461.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 159138225 + 5827396 = 12615^2 + 2414^2 .

It is a cyclic number.

It is not a de Polignac number, because 164965621 - 2³ = 164965613 is a prime.

It is a super-2 number, since 2×164965621² = 54427312223831282, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (164963621) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 82482810 + 82482811.

It is an arithmetic number, because the mean of its divisors is an integer number (82482811).

Almost surely, 2^164965621 is an apocalyptic number.

It is an amenable number.

164965621 is a deficient number, since it is larger than the sum of its proper divisors (1).

164965621 is an equidigital number, since it uses as much as digits as its factorization.

164965621 is an evil number, because the sum of its binary digits is even.

The product of its digits is 77760, while the sum is 40.

The square root of 164965621 is about 12843.8943081917. The cubic root of 164965621 is about 548.4425592307.

The spelling of 164965621 in words is "one hundred sixty-four million, nine hundred sixty-five thousand, six hundred twenty-one".