991187272 has 8 divisors (see below), whose sum is σ = 1858476150. Its totient is φ = 495593632.

The previous prime is 991187257. The next prime is 991187279. The reversal of 991187272 is 272781199.

It can be written as a sum of positive squares in only one way, i.e., 675272196 + 315915076 = 25986^2 + 17774^2 .

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

It is a hoax number, since the sum of its digits (46) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (991187279) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 61949197 + ... + 61949212.

Almost surely, 2^991187272 is an apocalyptic number.

It is an amenable number.

991187272 is a deficient number, since it is larger than the sum of its proper divisors (867288878).

991187272 is a wasteful number, since it uses less digits than its factorization.

991187272 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 123898415 (or 123898411 counting only the distinct ones).

The product of its digits is 127008, while the sum is 46.

The square root of 991187272 is about 31483.1267824529. The cubic root of 991187272 is about 997.0537521484.

The spelling of 991187272 in words is "nine hundred ninety-one million, one hundred eighty-seven thousand, two hundred seventy-two".