33820991 has 2 divisors, whose sum is σ = 33820992. Its totient is φ = 33820990.

The previous prime is 33820987. The next prime is 33820993. The reversal of 33820991 is 19902833.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 33820991 - 2² = 33820987 is a prime.

It is a super-2 number, since 2×33820991² = 2287718864444162, which contains 22 as substring.

It is a Sophie Germain prime.

Together with 33820993, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (33820993) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 16910495 + 16910496.

It is an arithmetic number, because the mean of its divisors is an integer number (16910496).

Almost surely, 2^33820991 is an apocalyptic number.

33820991 is a deficient number, since it is larger than the sum of its proper divisors (1).

33820991 is an equidigital number, since it uses as much as digits as its factorization.

33820991 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 11664, while the sum is 35.

The square root of 33820991 is about 5815.5817421819. The cubic root of 33820991 is about 323.3916307065.

The spelling of 33820991 in words is "thirty-three million, eight hundred twenty thousand, nine hundred ninety-one".