164521121 has 4 divisors (see below), whose sum is σ = 174198852. Its totient is φ = 154843392.

The previous prime is 164521109. The next prime is 164521127. The reversal of 164521121 is 121125461.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 121125461 = 4787 ⋅25303.

It can be written as a sum of positive squares in 2 ways, for example, as 45711121 + 118810000 = 6761^2 + 10900^2 .

It is a cyclic number.

It is not a de Polignac number, because 164521121 - 2¹⁴ = 164504737 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (164521127) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4838840 + ... + 4838873.

It is an arithmetic number, because the mean of its divisors is an integer number (43549713).

Almost surely, 2^164521121 is an apocalyptic number.

It is an amenable number.

164521121 is a deficient number, since it is larger than the sum of its proper divisors (9677731).

164521121 is an equidigital number, since it uses as much as digits as its factorization.

164521121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9677730.

The product of its digits is 480, while the sum is 23.

The square root of 164521121 is about 12826.5786942583. The cubic root of 164521121 is about 547.9495231625.

Adding to 164521121 its reverse (121125461), we get a palindrome (285646582).

The spelling of 164521121 in words is "one hundred sixty-four million, five hundred twenty-one thousand, one hundred twenty-one".