2191897207 has 4 divisors (see below), whose sum is σ = 2193073096. Its totient is φ = 2190721320.

The previous prime is 2191897199. The next prime is 2191897223. The reversal of 2191897207 is 7027981912.

2191897207 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 2191897207 - 2³ = 2191897199 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2191817207) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 585144 + ... + 588877.

It is an arithmetic number, because the mean of its divisors is an integer number (548268274).

Almost surely, 2^2191897207 is an apocalyptic number.

2191897207 is a deficient number, since it is larger than the sum of its proper divisors (1175889).

2191897207 is a wasteful number, since it uses less digits than its factorization.

2191897207 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1175888.

The product of its (nonzero) digits is 127008, while the sum is 46.

The square root of 2191897207 is about 46817.7018551744. The cubic root of 2191897207 is about 1298.9927517319.

The spelling of 2191897207 in words is "two billion, one hundred ninety-one million, eight hundred ninety-seven thousand, two hundred seven".