20909793791 has 2 divisors, whose sum is σ = 20909793792. Its totient is φ = 20909793790.

The previous prime is 20909793743. The next prime is 20909793823. The reversal of 20909793791 is 19739790902.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20909793791 - 2¹⁰ = 20909792767 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20909790791) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10454896895 + 10454896896.

It is an arithmetic number, because the mean of its divisors is an integer number (10454896896).

Almost surely, 2^20909793791 is an apocalyptic number.

20909793791 is a deficient number, since it is larger than the sum of its proper divisors (1).

20909793791 is an equidigital number, since it uses as much as digits as its factorization.

20909793791 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1928934, while the sum is 56.

The spelling of 20909793791 in words is "twenty billion, nine hundred nine million, seven hundred ninety-three thousand, seven hundred ninety-one".