2181258247891 has 2 divisors, whose sum is σ = 2181258247892. Its totient is φ = 2181258247890.

The previous prime is 2181258247837. The next prime is 2181258247933. The reversal of 2181258247891 is 1987428521812.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2181258247891 is a prime.

It is not a weakly prime, because it can be changed into another prime (2181258241891) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1090629123945 + 1090629123946.

It is an arithmetic number, because the mean of its divisors is an integer number (1090629123946).

Almost surely, 2^{2181258247891} is an apocalyptic number.

2181258247891 is a deficient number, since it is larger than the sum of its proper divisors (1).

2181258247891 is an equidigital number, since it uses as much as digits as its factorization.

2181258247891 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5160960, while the sum is 58.

The spelling of 2181258247891 in words is "two trillion, one hundred eighty-one billion, two hundred fifty-eight million, two hundred forty-seven thousand, eight hundred ninety-one".