20108591 has 2 divisors, whose sum is σ = 20108592. Its totient is φ = 20108590.

The previous prime is 20108551. The next prime is 20108597. The reversal of 20108591 is 19580102.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20108591 - 2²² = 15914287 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20108591.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20108597) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10054295 + 10054296.

It is an arithmetic number, because the mean of its divisors is an integer number (10054296).

Almost surely, 2^20108591 is an apocalyptic number.

20108591 is a deficient number, since it is larger than the sum of its proper divisors (1).

20108591 is an equidigital number, since it uses as much as digits as its factorization.

20108591 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 720, while the sum is 26.

The square root of 20108591 is about 4484.2603626462. The cubic root of 20108591 is about 271.9321440812.

Adding to 20108591 its reverse (19580102), we get a palindrome (39688693).

It can be divided in two parts, 2010 and 8591, that added together give a palindrome (10601).

The spelling of 20108591 in words is "twenty million, one hundred eight thousand, five hundred ninety-one".