18742181 has 2 divisors, whose sum is σ = 18742182. Its totient is φ = 18742180.

The previous prime is 18742159. The next prime is 18742183. The reversal of 18742181 is 18124781.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17724100 + 1018081 = 4210^2 + 1009^2 .

It is a cyclic number.

It is not a de Polignac number, because 18742181 - 2²² = 14547877 is a prime.

It is a super-2 number, since 2×18742181² = 702538697273522, which contains 22 as substring.

Together with 18742183, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18742183) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9371090 + 9371091.

It is an arithmetic number, because the mean of its divisors is an integer number (9371091).

Almost surely, 2^18742181 is an apocalyptic number.

It is an amenable number.

18742181 is a deficient number, since it is larger than the sum of its proper divisors (1).

18742181 is an equidigital number, since it uses as much as digits as its factorization.

18742181 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3584, while the sum is 32.

The square root of 18742181 is about 4329.2240644254. The cubic root of 18742181 is about 265.6277085952.

The spelling of 18742181 in words is "eighteen million, seven hundred forty-two thousand, one hundred eighty-one".