20513791 has 2 divisors, whose sum is σ = 20513792. Its totient is φ = 20513790.

The previous prime is 20513783. The next prime is 20513819. The reversal of 20513791 is 19731502.

It is an a-pointer prime, because the next prime (20513819) can be obtained adding 20513791 to its sum of digits (28).

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20513791 - 2³ = 20513783 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20513771) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10256895 + 10256896.

It is an arithmetic number, because the mean of its divisors is an integer number (10256896).

Almost surely, 2^20513791 is an apocalyptic number.

20513791 is a deficient number, since it is larger than the sum of its proper divisors (1).

20513791 is an equidigital number, since it uses as much as digits as its factorization.

20513791 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1890, while the sum is 28.

The square root of 20513791 is about 4529.2152741949. The cubic root of 20513791 is about 273.7465422164.

The spelling of 20513791 in words is "twenty million, five hundred thirteen thousand, seven hundred ninety-one".