1818181817 has 2 divisors, whose sum is σ = 1818181818. Its totient is φ = 1818181816.

The previous prime is 1818181787. The next prime is 1818181823. The reversal of 1818181817 is 7181818181.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1563332521 + 254849296 = 39539^2 + 15964^2 .

It is a cyclic number.

It is not a de Polignac number, because 1818181817 - 2²⁸ = 1549746361 is a prime.

It is a super-3 number, since 3×1818181817³ (a number of 29 digits) contains 333 as substring.

It is not a weakly prime, because it can be changed into another prime (1818187817) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 909090908 + 909090909.

It is an arithmetic number, because the mean of its divisors is an integer number (909090909).

Almost surely, 2^1818181817 is an apocalyptic number.

It is an amenable number.

1818181817 is a deficient number, since it is larger than the sum of its proper divisors (1).

1818181817 is an equidigital number, since it uses as much as digits as its factorization.

1818181817 is an evil number, because the sum of its binary digits is even.

The product of its digits is 28672, while the sum is 44.

The square root of 1818181817 is about 42640.1432572640. The cubic root of 1818181817 is about 1220.5224442058.

Adding to 1818181817 its reverse (7181818181), we get a palindrome (8999999998).

It can be divided in two parts, 1 and 818181817, that added together give a palindrome (818181818).

The spelling of 1818181817 in words is "one billion, eight hundred eighteen million, one hundred eighty-one thousand, eight hundred seventeen".