20791691 has 2 divisors, whose sum is σ = 20791692. Its totient is φ = 20791690.

The previous prime is 20791657. The next prime is 20791699. The reversal of 20791691 is 19619702.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20791691 - 2⁶ = 20791627 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 (20791699) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10395845 + 10395846.

It is an arithmetic number, because the mean of its divisors is an integer number (10395846).

Almost surely, 2^20791691 is an apocalyptic number.

20791691 is a deficient number, since it is larger than the sum of its proper divisors (1).

20791691 is an equidigital number, since it uses as much as digits as its factorization.

20791691 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 6804, while the sum is 35.

The square root of 20791691 is about 4559.7906750201. The cubic root of 20791691 is about 274.9771485144.

The spelling of 20791691 in words is "twenty million, seven hundred ninety-one thousand, six hundred ninety-one".