164721589 has 2 divisors, whose sum is σ = 164721590. Its totient is φ = 164721588.

The previous prime is 164721587. The next prime is 164721629. The reversal of 164721589 is 985127461.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 138250564 + 26471025 = 11758^2 + 5145^2 .

It is a cyclic number.

It is not a de Polignac number, because 164721589 - 2¹ = 164721587 is a prime.

Together with 164721587, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (164721587) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 82360794 + 82360795.

It is an arithmetic number, because the mean of its divisors is an integer number (82360795).

Almost surely, 2^164721589 is an apocalyptic number.

It is an amenable number.

164721589 is a deficient number, since it is larger than the sum of its proper divisors (1).

164721589 is an equidigital number, since it uses as much as digits as its factorization.

164721589 is an evil number, because the sum of its binary digits is even.

The product of its digits is 120960, while the sum is 43.

The square root of 164721589 is about 12834.3908698465. The cubic root of 164721589 is about 548.1719905653.

The spelling of 164721589 in words is "one hundred sixty-four million, seven hundred twenty-one thousand, five hundred eighty-nine".