20081797 has 2 divisors, whose sum is σ = 20081798. Its totient is φ = 20081796.

The previous prime is 20081779. The next prime is 20081821. The reversal of 20081797 is 79718002.

Together with previous prime (20081779) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18096516 + 1985281 = 4254^2 + 1409^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20081797 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20081197) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10040898 + 10040899.

It is an arithmetic number, because the mean of its divisors is an integer number (10040899).

Almost surely, 2^20081797 is an apocalyptic number.

It is an amenable number.

20081797 is a deficient number, since it is larger than the sum of its proper divisors (1).

20081797 is an equidigital number, since it uses as much as digits as its factorization.

20081797 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 7056, while the sum is 34.

The square root of 20081797 is about 4481.2718060836. The cubic root of 20081797 is about 271.8113103465.

Adding to 20081797 its reverse (79718002), we get a palindrome (99799799).

The spelling of 20081797 in words is "twenty million, eighty-one thousand, seven hundred ninety-seven".