991201265 has 8 divisors (see below), whose sum is σ = 1191643368. Its totient is φ = 791493120.

The previous prime is 991201249. The next prime is 991201271. The reversal of 991201265 is 562102199.

It can be written as a sum of positive squares in 4 ways, for example, as 89340304 + 901860961 = 9452^2 + 30031^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 991201265 - 2⁴ = 991201249 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 180512 + ... + 185921.

It is an arithmetic number, because the mean of its divisors is an integer number (148955421).

Almost surely, 2^991201265 is an apocalyptic number.

It is an amenable number.

991201265 is a deficient number, since it is larger than the sum of its proper divisors (200442103).

991201265 is a wasteful number, since it uses less digits than its factorization.

991201265 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 366979.

The product of its (nonzero) digits is 9720, while the sum is 35.

The square root of 991201265 is about 31483.3490118189. The cubic root of 991201265 is about 997.0584440662.

The spelling of 991201265 in words is "nine hundred ninety-one million, two hundred one thousand, two hundred sixty-five".