20091791 has 2 divisors, whose sum is σ = 20091792. Its totient is φ = 20091790.

The previous prime is 20091787. The next prime is 20091803. The reversal of 20091791 is 19719002.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20091791 - 2² = 20091787 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20091391) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10045895 + 10045896.

It is an arithmetic number, because the mean of its divisors is an integer number (10045896).

Almost surely, 2^20091791 is an apocalyptic number.

20091791 is a deficient number, since it is larger than the sum of its proper divisors (1).

20091791 is an equidigital number, since it uses as much as digits as its factorization.

20091791 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1134, while the sum is 29.

The square root of 20091791 is about 4482.3867526129. The cubic root of 20091791 is about 271.8563931600.

The spelling of 20091791 in words is "twenty million, ninety-one thousand, seven hundred ninety-one".