172169021 has 4 divisors (see below), whose sum is σ = 175087200. Its totient is φ = 169250844.

The previous prime is 172168999. The next prime is 172169057. The reversal of 172169021 is 120961271.

172169021 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 120961271 = 1277 ⋅94723.

It is a cyclic number.

It is not a de Polignac number, because 172169021 - 2⁶ = 172168957 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 (172169821) 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, 1459001 + ... + 1459118.

It is an arithmetic number, because the mean of its divisors is an integer number (43771800).

Almost surely, 2^172169021 is an apocalyptic number.

It is an amenable number.

172169021 is a deficient number, since it is larger than the sum of its proper divisors (2918179).

172169021 is an equidigital number, since it uses as much as digits as its factorization.

172169021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2918178.

The product of its (nonzero) digits is 1512, while the sum is 29.

The square root of 172169021 is about 13121.3193315307. The cubic root of 172169021 is about 556.3118829271.

The spelling of 172169021 in words is "one hundred seventy-two million, one hundred sixty-nine thousand, twenty-one".