791221889 has 2 divisors, whose sum is σ = 791221890. Its totient is φ = 791221888.

The previous prime is 791221859. The next prime is 791221891. The reversal of 791221889 is 988122197.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 745726864 + 45495025 = 27308^2 + 6745^2 .

It is a cyclic number.

It is not a de Polignac number, because 791221889 - 2²⁰ = 790173313 is a prime.

Together with 791221891, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (791221859) 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, 395610944 + 395610945.

It is an arithmetic number, because the mean of its divisors is an integer number (395610945).

Almost surely, 2^791221889 is an apocalyptic number.

It is an amenable number.

791221889 is a deficient number, since it is larger than the sum of its proper divisors (1).

791221889 is an equidigital number, since it uses as much as digits as its factorization.

791221889 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 145152, while the sum is 47.

The square root of 791221889 is about 28128.6666765419. Note that the first 4 decimals coincide. The cubic root of 791221889 is about 924.9099065894.

It can be divided in two parts, 79122188 and 9, that added together give a palindrome (79122197).

The spelling of 791221889 in words is "seven hundred ninety-one million, two hundred twenty-one thousand, eight hundred eighty-nine".