918821081 has 2 divisors, whose sum is σ = 918821082. Its totient is φ = 918821080.

The previous prime is 918821069. The next prime is 918821087. The reversal of 918821081 is 180128819.

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., 863184400 + 55636681 = 29380^2 + 7459^2 .

It is a cyclic number.

It is not a de Polignac number, because 918821081 - 2¹⁰ = 918820057 is a prime.

It is a super-2 number, since 2×918821081² = 1688464357780017122, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (918821087) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 459410540 + 459410541.

It is an arithmetic number, because the mean of its divisors is an integer number (459410541).

Almost surely, 2^918821081 is an apocalyptic number.

It is an amenable number.

918821081 is a deficient number, since it is larger than the sum of its proper divisors (1).

918821081 is an equidigital number, since it uses as much as digits as its factorization.

918821081 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 9216, while the sum is 38.

The square root of 918821081 is about 30312.0616421912. The cubic root of 918821081 is about 972.1732126099.

The spelling of 918821081 in words is "nine hundred eighteen million, eight hundred twenty-one thousand, eighty-one".