1991872 has 14 divisors (see below), whose sum is σ = 3952748. Its totient is φ = 995904.

The previous prime is 1991863. The next prime is 1991879. The reversal of 1991872 is 2781991.

It is not an unprimeable number, because it can be changed into a prime (1991879) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15498 + ... + 15625.

2^1991872 is an apocalyptic number.

It is an amenable number.

1991872 is a deficient number, since it is larger than the sum of its proper divisors (1960876).

1991872 is an equidigital number, since it uses as much as digits as its factorization.

1991872 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31135 (or 31125 counting only the distinct ones).

The product of its digits is 9072, while the sum is 37.

The square root of 1991872 is about 1411.3369548056. The cubic root of 1991872 is about 125.8211959503.

The spelling of 1991872 in words is "one million, nine hundred ninety-one thousand, eight hundred seventy-two".