164435581 has 2 divisors, whose sum is σ = 164435582. Its totient is φ = 164435580.

The previous prime is 164435573. The next prime is 164435591. The reversal of 164435581 is 185534461.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 162333081 + 2102500 = 12741^2 + 1450^2 .

It is a cyclic number.

It is not a de Polignac number, because 164435581 - 2³ = 164435573 is a prime.

It is a super-3 number, since 3×164435581³ (a number of 26 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a self number, because there is not a number n which added to its sum of digits gives 164435581.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (164435591) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 82217790 + 82217791.

It is an arithmetic number, because the mean of its divisors is an integer number (82217791).

Almost surely, 2^164435581 is an apocalyptic number.

It is an amenable number.

164435581 is a deficient number, since it is larger than the sum of its proper divisors (1).

164435581 is an equidigital number, since it uses as much as digits as its factorization.

164435581 is an evil number, because the sum of its binary digits is even.

The product of its digits is 57600, while the sum is 37.

The square root of 164435581 is about 12823.2437783893. The cubic root of 164435581 is about 547.8545409749.

The spelling of 164435581 in words is "one hundred sixty-four million, four hundred thirty-five thousand, five hundred eighty-one".