1991272 has 8 divisors (see below), whose sum is σ = 3733650. Its totient is φ = 995632.

The previous prime is 1991267. The next prime is 1991279. The reversal of 1991272 is 2721991.

It can be written as a sum of positive squares in only one way, i.e., 1865956 + 125316 = 1366^2 + 354^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is not an unprimeable number, because it can be changed into a prime (1991279) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 124447 + ... + 124462.

2^1991272 is an apocalyptic number.

It is an amenable number.

1991272 is a deficient number, since it is larger than the sum of its proper divisors (1742378).

1991272 is a wasteful number, since it uses less digits than its factorization.

1991272 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 248915 (or 248911 counting only the distinct ones).

The product of its digits is 2268, while the sum is 31.

The square root of 1991272 is about 1411.1243743909. The cubic root of 1991272 is about 125.8085612196.

The spelling of 1991272 in words is "one million, nine hundred ninety-one thousand, two hundred seventy-two".