164693581 has 8 divisors (see below), whose sum is σ = 183478680. Its totient is φ = 146782272.

The previous prime is 164693579. The next prime is 164693609. The reversal of 164693581 is 185396461.

It can be written as a sum of positive squares in 4 ways, for example, as 84681 + 164608900 = 291^2 + 12830^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 164693581 - 2¹ = 164693579 is a prime.

It is a super-2 number, since 2×164693581² = 54247951245207122, which 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 (164693531) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 218050 + ... + 218803.

It is an arithmetic number, because the mean of its divisors is an integer number (22934835).

Almost surely, 2^164693581 is an apocalyptic number.

It is an amenable number.

164693581 is a deficient number, since it is larger than the sum of its proper divisors (18785099).

164693581 is a wasteful number, since it uses less digits than its factorization.

164693581 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 436895.

The product of its digits is 155520, while the sum is 43.

The square root of 164693581 is about 12833.2996925966. The cubic root of 164693581 is about 548.1409198124.

The spelling of 164693581 in words is "one hundred sixty-four million, six hundred ninety-three thousand, five hundred eighty-one".