20845091 has 2 divisors, whose sum is σ = 20845092. Its totient is φ = 20845090.

The previous prime is 20845073. The next prime is 20845129. The reversal of 20845091 is 19054802.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20845091 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (20845021) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10422545 + 10422546.

It is an arithmetic number, because the mean of its divisors is an integer number (10422546).

Almost surely, 2^20845091 is an apocalyptic number.

20845091 is a deficient number, since it is larger than the sum of its proper divisors (1).

20845091 is an equidigital number, since it uses as much as digits as its factorization.

20845091 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2880, while the sum is 29.

The square root of 20845091 is about 4565.6424520543. The cubic root of 20845091 is about 275.2123582862.

Adding to 20845091 its reverse (19054802), we get a palindrome (39899893).

The spelling of 20845091 in words is "twenty million, eight hundred forty-five thousand, ninety-one".