18949181 has 2 divisors, whose sum is σ = 18949182. Its totient is φ = 18949180.

The previous prime is 18949159. The next prime is 18949211. The reversal of 18949181 is 18194981.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13468900 + 5480281 = 3670^2 + 2341^2 .

It is a cyclic number.

It is not a de Polignac number, because 18949181 - 2²² = 14754877 is a prime.

It is a super-2 number, since 2×18949181² = 718142921141522, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18949081) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9474590 + 9474591.

It is an arithmetic number, because the mean of its divisors is an integer number (9474591).

Almost surely, 2^18949181 is an apocalyptic number.

It is an amenable number.

18949181 is a deficient number, since it is larger than the sum of its proper divisors (1).

18949181 is an equidigital number, since it uses as much as digits as its factorization.

18949181 is an evil number, because the sum of its binary digits is even.

The product of its digits is 20736, while the sum is 41.

The square root of 18949181 is about 4353.0657013190. The cubic root of 18949181 is about 266.6020480582.

The spelling of 18949181 in words is "eighteen million, nine hundred forty-nine thousand, one hundred eighty-one".