33390221 has 4 divisors (see below), whose sum is σ = 33405372. Its totient is φ = 33375072.

The previous prime is 33390191. The next prime is 33390233. The reversal of 33390221 is 12209333.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12209333 = 61 ⋅200153.

It can be written as a sum of positive squares in 2 ways, for example, as 9517225 + 23872996 = 3085^2 + 4886^2 .

It is a cyclic number.

It is not a de Polignac number, because 33390221 - 2⁶ = 33390157 is a prime.

It is a super-2 number, since 2×33390221² = 2229813716857682, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (33390271) 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, 3560 + ... + 8913.

It is an arithmetic number, because the mean of its divisors is an integer number (8351343).

Almost surely, 2^33390221 is an apocalyptic number.

It is an amenable number.

33390221 is a deficient number, since it is larger than the sum of its proper divisors (15151).

33390221 is a wasteful number, since it uses less digits than its factorization.

33390221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15150.

The product of its (nonzero) digits is 972, while the sum is 23.

The square root of 33390221 is about 5778.4272081597. The cubic root of 33390221 is about 322.0127722773.

Adding to 33390221 its reverse (12209333), we get a palindrome (45599554).

The spelling of 33390221 in words is "thirty-three million, three hundred ninety thousand, two hundred twenty-one".