18444261691 has 2 divisors, whose sum is σ = 18444261692. Its totient is φ = 18444261690.

The previous prime is 18444261679. The next prime is 18444261701. The reversal of 18444261691 is 19616244481.

It is a strong prime.

It is an emirp because it is prime and its reverse (19616244481) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18444261691 - 2⁹ = 18444261179 is a prime.

It is not a weakly prime, because it can be changed into another prime (18444261391) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9222130845 + 9222130846.

It is an arithmetic number, because the mean of its divisors is an integer number (9222130846).

Almost surely, 2^18444261691 is an apocalyptic number.

18444261691 is a deficient number, since it is larger than the sum of its proper divisors (1).

18444261691 is an equidigital number, since it uses as much as digits as its factorization.

18444261691 is an evil number, because the sum of its binary digits is even.

The product of its digits is 331776, while the sum is 46.

The spelling of 18444261691 in words is "eighteen billion, four hundred forty-four million, two hundred sixty-one thousand, six hundred ninety-one".