991125005 has 12 divisors (see below), whose sum is σ = 1287877140. Its totient is φ = 731907072.

The previous prime is 991124999. The next prime is 991125071. The reversal of 991125005 is 500521199.

It can be written as a sum of positive squares in 6 ways, for example, as 327392836 + 663732169 = 18094^2 + 25763^2 .

It is not a de Polignac number, because 991125005 - 2⁴ = 991124989 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 585620 + ... + 587309.

It is an arithmetic number, because the mean of its divisors is an integer number (107323095).

Almost surely, 2^991125005 is an apocalyptic number.

It is an amenable number.

991125005 is a deficient number, since it is larger than the sum of its proper divisors (296752135).

991125005 is a wasteful number, since it uses less digits than its factorization.

991125005 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1172960 (or 1172947 counting only the distinct ones).

The product of its (nonzero) digits is 4050, while the sum is 32.

The square root of 991125005 is about 31482.1378721331. The cubic root of 991125005 is about 997.0328731993.

The spelling of 991125005 in words is "nine hundred ninety-one million, one hundred twenty-five thousand, five".