2191506899 has 2 divisors, whose sum is σ = 2191506900. Its totient is φ = 2191506898.

The previous prime is 2191506893. The next prime is 2191507027. The reversal of 2191506899 is 9986051912.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 2191506899 - 2⁴ = 2191506883 is a prime.

It is a Sophie Germain prime.

It is not a weakly prime, because it can be changed into another prime (2191506893) by changing a digit.

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 as a sum of consecutive naturals, namely, 1095753449 + 1095753450.

It is an arithmetic number, because the mean of its divisors is an integer number (1095753450).

Almost surely, 2^2191506899 is an apocalyptic number.

2191506899 is a deficient number, since it is larger than the sum of its proper divisors (1).

2191506899 is an equidigital number, since it uses as much as digits as its factorization.

2191506899 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 349920, while the sum is 50.

The square root of 2191506899 is about 46813.5332889967. The cubic root of 2191506899 is about 1298.9156438945.

The spelling of 2191506899 in words is "two billion, one hundred ninety-one million, five hundred six thousand, eight hundred ninety-nine".