818491493 has 2 divisors, whose sum is σ = 818491494. Its totient is φ = 818491492.

The previous prime is 818491441. The next prime is 818491517. The reversal of 818491493 is 394194818.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 818360449 + 131044 = 28607^2 + 362^2 .

It is a cyclic number.

It is not a de Polignac number, because 818491493 - 2¹⁰ = 818490469 is a prime.

It is a super-2 number, since 2×818491493² = 1339856648226738098, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (818491433) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 409245746 + 409245747.

It is an arithmetic number, because the mean of its divisors is an integer number (409245747).

Almost surely, 2^818491493 is an apocalyptic number.

It is an amenable number.

818491493 is a deficient number, since it is larger than the sum of its proper divisors (1).

818491493 is an equidigital number, since it uses as much as digits as its factorization.

818491493 is an evil number, because the sum of its binary digits is even.

The product of its digits is 248832, while the sum is 47.

The square root of 818491493 is about 28609.2903267453. The cubic root of 818491493 is about 935.4158475075.

The spelling of 818491493 in words is "eight hundred eighteen million, four hundred ninety-one thousand, four hundred ninety-three".