18491771 has 2 divisors, whose sum is σ = 18491772. Its totient is φ = 18491770.

The previous prime is 18491719. The next prime is 18491773. The reversal of 18491771 is 17719481.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18491771 is a prime.

Together with 18491773, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (18491773) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9245885 + 9245886.

It is an arithmetic number, because the mean of its divisors is an integer number (9245886).

Almost surely, 2^18491771 is an apocalyptic number.

18491771 is a deficient number, since it is larger than the sum of its proper divisors (1).

18491771 is an equidigital number, since it uses as much as digits as its factorization.

18491771 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 14112, while the sum is 38.

The square root of 18491771 is about 4300.2059253017. The cubic root of 18491771 is about 264.4394035019.

The spelling of 18491771 in words is "eighteen million, four hundred ninety-one thousand, seven hundred seventy-one".