1991789448 has 32 divisors (see below), whose sum is σ = 5432153760. Its totient is φ = 603572480.

The previous prime is 1991789441. The next prime is 1991789477. The reversal of 1991789448 is 8449871991.

It is a junction number, because it is equal to n+sod(n) for n = 1991789391 and 1991789400.

It is not an unprimeable number, because it can be changed into a prime (1991789441) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3772065 + ... + 3772592.

It is an arithmetic number, because the mean of its divisors is an integer number (169754805).

Almost surely, 2^1991789448 is an apocalyptic number.

It is an amenable number.

1991789448 is an abundant number, since it is smaller than the sum of its proper divisors (3440364312).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1991789448 is a wasteful number, since it uses less digits than its factorization.

1991789448 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7544677 (or 7544673 counting only the distinct ones).

The product of its digits is 5225472, while the sum is 60.

The square root of 1991789448 is about 44629.4683813285. The cubic root of 1991789448 is about 1258.1945773036.

The spelling of 1991789448 in words is "one billion, nine hundred ninety-one million, seven hundred eighty-nine thousand, four hundred forty-eight".