172066621 has 4 divisors (see below), whose sum is σ = 174423772. Its totient is φ = 169709472.

The previous prime is 172066591. The next prime is 172066633. The reversal of 172066621 is 126660271.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 126660271 = 2593 ⋅48847.

It can be written as a sum of positive squares in 2 ways, for example, as 60996100 + 111070521 = 7810^2 + 10539^2 .

It is a cyclic number.

It is not a de Polignac number, because 172066621 - 2⁵ = 172066589 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (172066691) 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, 1178466 + ... + 1178611.

It is an arithmetic number, because the mean of its divisors is an integer number (43605943).

Almost surely, 2^172066621 is an apocalyptic number.

It is an amenable number.

172066621 is a deficient number, since it is larger than the sum of its proper divisors (2357151).

172066621 is an equidigital number, since it uses as much as digits as its factorization.

172066621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2357150.

The product of its (nonzero) digits is 6048, while the sum is 31.

The square root of 172066621 is about 13117.4167045192. The cubic root of 172066621 is about 556.2015695578.

The spelling of 172066621 in words is "one hundred seventy-two million, sixty-six thousand, six hundred twenty-one".