812166660 has 36 divisors (see below), whose sum is σ = 2463572748. Its totient is φ = 216577728.

The previous prime is 812166659. The next prime is 812166709. The reversal of 812166660 is 66661218.

It can be written as a sum of positive squares in 2 ways, for example, as 502477056 + 309689604 = 22416^2 + 17598^2 .

It is a tau number, because it is divible by the number of its divisors (36).

It is a super-2 number, since 2×812166660² = 1319229367231111200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2255839 + ... + 2256198.

Almost surely, 2^812166660 is an apocalyptic number.

It is an amenable number.

812166660 is an abundant number, since it is smaller than the sum of its proper divisors (1651406088).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

812166660 is a wasteful number, since it uses less digits than its factorization.

812166660 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4512052 (or 4512047 counting only the distinct ones).

The product of its (nonzero) digits is 20736, while the sum is 36.

The square root of 812166660 is about 28498.5378572305. The cubic root of 812166660 is about 933.0001619779. Note that the first 3 decimals are identical.

The spelling of 812166660 in words is "eight hundred twelve million, one hundred sixty-six thousand, six hundred sixty".