20847791 has 2 divisors, whose sum is σ = 20847792. Its totient is φ = 20847790.

The previous prime is 20847767. The next prime is 20847793. The reversal of 20847791 is 19774802.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20847791 - 2⁶ = 20847727 is a prime.

Together with 20847793, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20847793) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10423895 + 10423896.

It is an arithmetic number, because the mean of its divisors is an integer number (10423896).

Almost surely, 2^20847791 is an apocalyptic number.

20847791 is a deficient number, since it is larger than the sum of its proper divisors (1).

20847791 is an equidigital number, since it uses as much as digits as its factorization.

20847791 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 28224, while the sum is 38.

The square root of 20847791 is about 4565.9381292348. The cubic root of 20847791 is about 275.2242402410.

The spelling of 20847791 in words is "twenty million, eight hundred forty-seven thousand, seven hundred ninety-one".