33172421 has 4 divisors (see below), whose sum is σ = 33217344. Its totient is φ = 33127500.

The previous prime is 33172409. The next prime is 33172427. The reversal of 33172421 is 12427133.

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: 12427133 = 137 ⋅90709.

It is a cyclic number.

It is not a de Polignac number, because 33172421 - 2⁶ = 33172357 is a prime.

It is a super-2 number, since 2×33172421² = 2200819030002482, 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 (33172427) 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, 21335 + ... + 22836.

It is an arithmetic number, because the mean of its divisors is an integer number (8304336).

Almost surely, 2^33172421 is an apocalyptic number.

It is an amenable number.

33172421 is a deficient number, since it is larger than the sum of its proper divisors (44923).

33172421 is an equidigital number, since it uses as much as digits as its factorization.

33172421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 44922.

The product of its digits is 1008, while the sum is 23.

The square root of 33172421 is about 5759.5504164822. The cubic root of 33172421 is about 321.3110954874.

Adding to 33172421 its reverse (12427133), we get a palindrome (45599554).

The spelling of 33172421 in words is "thirty-three million, one hundred seventy-two thousand, four hundred twenty-one".