18189443971 has 2 divisors, whose sum is σ = 18189443972. Its totient is φ = 18189443970.

The previous prime is 18189443969. The next prime is 18189444011. The reversal of 18189443971 is 17934498181.

It is a happy number.

It is a weak prime.

It is an emirp because it is prime and its reverse (17934498181) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18189443971 - 2¹ = 18189443969 is a prime.

Together with 18189443969, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (18189441971) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9094721985 + 9094721986.

It is an arithmetic number, because the mean of its divisors is an integer number (9094721986).

Almost surely, 2^18189443971 is an apocalyptic number.

18189443971 is a deficient number, since it is larger than the sum of its proper divisors (1).

18189443971 is an equidigital number, since it uses as much as digits as its factorization.

18189443971 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1741824, while the sum is 55.

The spelling of 18189443971 in words is "eighteen billion, one hundred eighty-nine million, four hundred forty-three thousand, nine hundred seventy-one".