33431221 has 2 divisors, whose sum is σ = 33431222. Its totient is φ = 33431220.

The previous prime is 33431219. The next prime is 33431227. The reversal of 33431221 is 12213433.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 23280625 + 10150596 = 4825^2 + 3186^2 .

It is a cyclic number.

It is not a de Polignac number, because 33431221 - 2¹ = 33431219 is a prime.

It is a super-2 number, since 2×33431221² = 2235293075101682, which contains 22 as substring.

Together with 33431219, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (33431227) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 16715610 + 16715611.

It is an arithmetic number, because the mean of its divisors is an integer number (16715611).

Almost surely, 2^33431221 is an apocalyptic number.

It is an amenable number.

33431221 is a deficient number, since it is larger than the sum of its proper divisors (1).

33431221 is an equidigital number, since it uses as much as digits as its factorization.

33431221 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 432, while the sum is 19.

The square root of 33431221 is about 5781.9737979344. The cubic root of 33431221 is about 322.1445186703.

Adding to 33431221 its reverse (12213433), we get a palindrome (45644654).

The spelling of 33431221 in words is "thirty-three million, four hundred thirty-one thousand, two hundred twenty-one".