1991081125 has 16 divisors (see below), whose sum is σ = 2710768320. Its totient is φ = 1448058000.

The previous prime is 1991081093. The next prime is 1991081153. The reversal of 1991081125 is 5211801991.

1991081125 is digitally balanced in base 6, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 1991081125 - 2⁵ = 1991081093 is a prime.

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 15 ways as a sum of consecutive naturals, for example, 722655 + ... + 725404.

It is an arithmetic number, because the mean of its divisors is an integer number (169423020).

Almost surely, 2^1991081125 is an apocalyptic number.

It is an amenable number.

1991081125 is a deficient number, since it is larger than the sum of its proper divisors (719687195).

1991081125 is a wasteful number, since it uses less digits than its factorization.

1991081125 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1448085 (or 1448075 counting only the distinct ones).

The product of its (nonzero) digits is 6480, while the sum is 37.

The square root of 1991081125 is about 44621.5320781347. The cubic root of 1991081125 is about 1258.0454126377.

The spelling of 1991081125 in words is "one billion, nine hundred ninety-one million, eighty-one thousand, one hundred twenty-five".