2191304987 has 2 divisors, whose sum is σ = 2191304988. Its totient is φ = 2191304986.

The previous prime is 2191304963. The next prime is 2191304993. The reversal of 2191304987 is 7894031912.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 2191304987 - 2¹⁰ = 2191303963 is a prime.

It is not a weakly prime, because it can be changed into another prime (2191304587) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1095652493 + 1095652494.

It is an arithmetic number, because the mean of its divisors is an integer number (1095652494).

Almost surely, 2^2191304987 is an apocalyptic number.

2191304987 is a deficient number, since it is larger than the sum of its proper divisors (1).

2191304987 is an equidigital number, since it uses as much as digits as its factorization.

2191304987 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 108864, while the sum is 44.

The square root of 2191304987 is about 46811.3766834516. The cubic root of 2191304987 is about 1298.8757512966.

The spelling of 2191304987 in words is "two billion, one hundred ninety-one million, three hundred four thousand, nine hundred eighty-seven".