164804042581 has 4 divisors (see below), whose sum is σ = 169258205932. Its totient is φ = 160349879232.

The previous prime is 164804042569. The next prime is 164804042591. The reversal of 164804042581 is 185240408461.

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 91693290481 + 73110752100 = 302809^2 + 270390^2 .

It is a cyclic number.

It is not a de Polignac number, because 164804042581 - 2⁷ = 164804042453 is a prime.

It is a super-2 number, since 2×164804042581² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (164804042591) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2227081620 + ... + 2227081693.

It is an arithmetic number, because the mean of its divisors is an integer number (42314551483).

Almost surely, 2^164804042581 is an apocalyptic number.

It is an amenable number.

164804042581 is a deficient number, since it is larger than the sum of its proper divisors (4454163351).

164804042581 is an equidigital number, since it uses as much as digits as its factorization.

164804042581 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4454163350.

The product of its (nonzero) digits is 245760, while the sum is 43.

The spelling of 164804042581 in words is "one hundred sixty-four billion, eight hundred four million, forty-two thousand, five hundred eighty-one".