991538045 has 8 divisors (see below), whose sum is σ = 1212295896. Its totient is φ = 778263616.

The previous prime is 991538033. The next prime is 991538063. The reversal of 991538045 is 540835199.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 79316836 + 912221209 = 8906^2 + 30203^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 991538045 - 2⁴ = 991538029 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 991537987 and 991538005.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1870562 + ... + 1871091.

It is an arithmetic number, because the mean of its divisors is an integer number (151536987).

Almost surely, 2^991538045 is an apocalyptic number.

It is an amenable number.

991538045 is a deficient number, since it is larger than the sum of its proper divisors (220757851).

991538045 is a wasteful number, since it uses less digits than its factorization.

991538045 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3741711.

The product of its (nonzero) digits is 194400, while the sum is 44.

The square root of 991538045 is about 31488.6970991180. The cubic root of 991538045 is about 997.1713546430.

The spelling of 991538045 in words is "nine hundred ninety-one million, five hundred thirty-eight thousand, forty-five".