818989945 has 4 divisors (see below), whose sum is σ = 982787940. Its totient is φ = 655191952.

The previous prime is 818989937. The next prime is 818989979. The reversal of 818989945 is 549989818.

818989945 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 169963369 + 649026576 = 13037^2 + 25476^2 .

It is a cyclic number.

It is not a de Polignac number, because 818989945 - 2³ = 818989937 is a prime.

It is a super-2 number, since 2×818989945² = 1341489060022206050, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 81898990 + ... + 81898999.

It is an arithmetic number, because the mean of its divisors is an integer number (245696985).

Almost surely, 2^818989945 is an apocalyptic number.

It is an amenable number.

818989945 is a deficient number, since it is larger than the sum of its proper divisors (163797995).

818989945 is a wasteful number, since it uses less digits than its factorization.

818989945 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 163797994.

The product of its digits is 7464960, while the sum is 61.

The square root of 818989945 is about 28618.0003669019. Note that the first 3 decimals coincide. The cubic root of 818989945 is about 935.6056948413.

The spelling of 818989945 in words is "eight hundred eighteen million, nine hundred eighty-nine thousand, nine hundred forty-five".