164326581 has 6 divisors (see below), whose sum is σ = 237360630. Its totient is φ = 109551048.

The previous prime is 164326543. The next prime is 164326609. The reversal of 164326581 is 185623461.

It is a happy number.

164326581 is a `hidden beast` number, since 1 + 643 + 2 + 6 + 5 + 8 + 1 = 666.

It can be written as a sum of positive squares in only one way, i.e., 154778481 + 9548100 = 12441^2 + 3090^2 .

It is not a de Polignac number, because 164326581 - 2⁷ = 164326453 is a prime.

It is a super-2 number, since 2×164326581² = 54006450446299122, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (164326511) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 9129246 + ... + 9129263.

It is an arithmetic number, because the mean of its divisors is an integer number (39560105).

Almost surely, 2^164326581 is an apocalyptic number.

It is an amenable number.

164326581 is a deficient number, since it is larger than the sum of its proper divisors (73034049).

164326581 is a wasteful number, since it uses less digits than its factorization.

164326581 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18258515 (or 18258512 counting only the distinct ones).

The product of its digits is 34560, while the sum is 36.

The square root of 164326581 is about 12818.9929791696. The cubic root of 164326581 is about 547.7334614530.

It can be divided in two parts, 1643 and 26581, that added together give a square (28224 = 168²).

The spelling of 164326581 in words is "one hundred sixty-four million, three hundred twenty-six thousand, five hundred eighty-one".