2191011945 has 16 divisors (see below), whose sum is σ = 3521067840. Its totient is φ = 1163390144.

The previous prime is 2191011941. The next prime is 2191012027. The reversal of 2191011945 is 5491101912.

It is a cyclic number.

It is not a de Polignac number, because 2191011945 - 2² = 2191011941 is a prime.

It is not an unprimeable number, because it can be changed into a prime (2191011941) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 318330 + ... + 325139.

It is an arithmetic number, because the mean of its divisors is an integer number (220066740).

Almost surely, 2^2191011945 is an apocalyptic number.

It is an amenable number.

2191011945 is a deficient number, since it is larger than the sum of its proper divisors (1330055895).

2191011945 is a wasteful number, since it uses less digits than its factorization.

2191011945 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 643704.

The product of its (nonzero) digits is 3240, while the sum is 33.

The square root of 2191011945 is about 46808.2465490858. The cubic root of 2191011945 is about 1298.8178494043.

The spelling of 2191011945 in words is "two billion, one hundred ninety-one million, eleven thousand, nine hundred forty-five".