20913811 has 2 divisors, whose sum is σ = 20913812. Its totient is φ = 20913810.

The previous prime is 20913803. The next prime is 20913829. The reversal of 20913811 is 11831902.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20913811 - 2³ = 20913803 is a prime.

It is not a weakly prime, because it can be changed into another prime (20913881) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10456905 + 10456906.

It is an arithmetic number, because the mean of its divisors is an integer number (10456906).

Almost surely, 2^20913811 is an apocalyptic number.

20913811 is a deficient number, since it is larger than the sum of its proper divisors (1).

20913811 is an equidigital number, since it uses as much as digits as its factorization.

20913811 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 432, while the sum is 25.

The square root of 20913811 is about 4573.1620351787. The cubic root of 20913811 is about 275.5144573623.

The spelling of 20913811 in words is "twenty million, nine hundred thirteen thousand, eight hundred eleven".