18494981 has 2 divisors, whose sum is σ = 18494982. Its totient is φ = 18494980.

The previous prime is 18494909. The next prime is 18495007. The reversal of 18494981 is 18949481.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 9821956 + 8673025 = 3134^2 + 2945^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18494981 is a prime.

It is a super-2 number, since 2×18494981² = 684128644380722, 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 (18494381) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9247490 + 9247491.

It is an arithmetic number, because the mean of its divisors is an integer number (9247491).

Almost surely, 2^18494981 is an apocalyptic number.

It is an amenable number.

18494981 is a deficient number, since it is larger than the sum of its proper divisors (1).

18494981 is an equidigital number, since it uses as much as digits as its factorization.

18494981 is an evil number, because the sum of its binary digits is even.

The product of its digits is 82944, while the sum is 44.

The square root of 18494981 is about 4300.5791470452. The cubic root of 18494981 is about 264.4547040262.

The spelling of 18494981 in words is "eighteen million, four hundred ninety-four thousand, nine hundred eighty-one".