164685989 has 4 divisors (see below), whose sum is σ = 177354156. Its totient is φ = 152017824.

The previous prime is 164685973. The next prime is 164686009. The reversal of 164685989 is 989586461.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 24453025 + 140232964 = 4945^2 + 11842^2 .

It is a cyclic number.

It is not a de Polignac number, because 164685989 - 2⁴ = 164685973 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (164685959) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6334064 + ... + 6334089.

It is an arithmetic number, because the mean of its divisors is an integer number (44338539).

Almost surely, 2^164685989 is an apocalyptic number.

It is an amenable number.

164685989 is a deficient number, since it is larger than the sum of its proper divisors (12668167).

164685989 is a wasteful number, since it uses less digits than its factorization.

164685989 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12668166.

The product of its digits is 3732480, while the sum is 56.

The square root of 164685989 is about 12833.0038962045. The cubic root of 164685989 is about 548.1324969992.

The spelling of 164685989 in words is "one hundred sixty-four million, six hundred eighty-five thousand, nine hundred eighty-nine".