844120891 has 4 divisors (see below), whose sum is σ = 844367832. Its totient is φ = 843873952.

The previous prime is 844120889. The next prime is 844120897. The reversal of 844120891 is 198021448.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 844120891 - 2¹ = 844120889 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 844120891.

It is not an unprimeable number, because it can be changed into a prime (844120897) 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 in 3 ways as a sum of consecutive naturals, for example, 118270 + ... + 125203.

It is an arithmetic number, because the mean of its divisors is an integer number (211091958).

Almost surely, 2^844120891 is an apocalyptic number.

844120891 is a deficient number, since it is larger than the sum of its proper divisors (246941).

844120891 is a wasteful number, since it uses less digits than its factorization.

844120891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 246940.

The product of its (nonzero) digits is 18432, while the sum is 37.

The square root of 844120891 is about 29053.7586380833. The cubic root of 844120891 is about 945.0792244359.

The spelling of 844120891 in words is "eight hundred forty-four million, one hundred twenty thousand, eight hundred ninety-one".