164989681 has 2 divisors, whose sum is σ = 164989682. Its totient is φ = 164989680.

The previous prime is 164989679. The next prime is 164989687. The reversal of 164989681 is 186989461.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 120099681 + 44890000 = 10959^2 + 6700^2 .

It is a cyclic number.

It is not a de Polignac number, because 164989681 - 2¹ = 164989679 is a prime.

It is a super-2 number, since 2×164989681² = 54443189672963522, which contains 22 as substring.

Together with 164989679, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (164989687) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 82494840 + 82494841.

It is an arithmetic number, because the mean of its divisors is an integer number (82494841).

Almost surely, 2^164989681 is an apocalyptic number.

It is an amenable number.

164989681 is a deficient number, since it is larger than the sum of its proper divisors (1).

164989681 is an equidigital number, since it uses as much as digits as its factorization.

164989681 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 746496, while the sum is 52.

The square root of 164989681 is about 12844.8309058547. The cubic root of 164989681 is about 548.4692211223.

The spelling of 164989681 in words is "one hundred sixty-four million, nine hundred eighty-nine thousand, six hundred eighty-one".