164312521 has 4 divisors (see below), whose sum is σ = 169978500. Its totient is φ = 158646544.

The previous prime is 164312441. The next prime is 164312539. The reversal of 164312521 is 125213461.

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 58736896 + 105575625 = 7664^2 + 10275^2 .

It is a cyclic number.

It is not a de Polignac number, because 164312521 - 2¹¹ = 164310473 is a prime.

It is a super-4 number, since 4×164312521⁴ (a number of 34 digits) contains 4444 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (164312321) 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, 2832946 + ... + 2833003.

It is an arithmetic number, because the mean of its divisors is an integer number (42494625).

Almost surely, 2^164312521 is an apocalyptic number.

It is an amenable number.

164312521 is a deficient number, since it is larger than the sum of its proper divisors (5665979).

164312521 is an equidigital number, since it uses as much as digits as its factorization.

164312521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5665978.

The product of its digits is 1440, while the sum is 25.

The square root of 164312521 is about 12818.4445624264. Note that the first 3 decimals coincide. The cubic root of 164312521 is about 547.7178394072.

Adding to 164312521 its reverse (125213461), we get a palindrome (289525982).

The spelling of 164312521 in words is "one hundred sixty-four million, three hundred twelve thousand, five hundred twenty-one".