1818181997 has 2 divisors, whose sum is σ = 1818181998. Its totient is φ = 1818181996.

The previous prime is 1818181969. The next prime is 1818182053. The reversal of 1818181997 is 7991818181.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1464516361 + 353665636 = 38269^2 + 18806^2 .

It is a cyclic number.

It is not a de Polignac number, because 1818181997 - 2⁶ = 1818181933 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1818181927) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 909090998 + 909090999.

It is an arithmetic number, because the mean of its divisors is an integer number (909090999).

Almost surely, 2^1818181997 is an apocalyptic number.

It is an amenable number.

1818181997 is a deficient number, since it is larger than the sum of its proper divisors (1).

1818181997 is an equidigital number, since it uses as much as digits as its factorization.

1818181997 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 290304, while the sum is 53.

The square root of 1818181997 is about 42640.1453679511. The cubic root of 1818181997 is about 1220.5224844831.

The spelling of 1818181997 in words is "one billion, eight hundred eighteen million, one hundred eighty-one thousand, nine hundred ninety-seven".