33391921 has 2 divisors, whose sum is σ = 33391922. Its totient is φ = 33391920.

The previous prime is 33391903. The next prime is 33391931. The reversal of 33391921 is 12919333.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 32080896 + 1311025 = 5664^2 + 1145^2 .

It is a cyclic number.

It is not a de Polignac number, because 33391921 - 2⁹ = 33391409 is a prime.

It is a super-2 number, since 2×33391921² = 2230040776140482, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (33391931) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 16695960 + 16695961.

It is an arithmetic number, because the mean of its divisors is an integer number (16695961).

Almost surely, 2^33391921 is an apocalyptic number.

It is an amenable number.

33391921 is a deficient number, since it is larger than the sum of its proper divisors (1).

33391921 is an equidigital number, since it uses as much as digits as its factorization.

33391921 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4374, while the sum is 31.

The square root of 33391921 is about 5778.5743051379. The cubic root of 33391921 is about 322.0182370752.

The spelling of 33391921 in words is "thirty-three million, three hundred ninety-one thousand, nine hundred twenty-one".