809866512 has 420 divisors, whose sum is σ = 2974249740. Its totient is φ = 211631616.

The previous prime is 809866493. The next prime is 809866543. The reversal of 809866512 is 215668908.

It can be written as a sum of positive squares in 2 ways, for example, as 329204736 + 480661776 = 18144^2 + 21924^2 .

It is a super-2 number, since 2×809866512² = 1311767534518092288, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 83 ways as a sum of consecutive naturals, for example, 7429914 + ... + 7430022.

It is an arithmetic number, because the mean of its divisors is an integer number (7081547).

Almost surely, 2^809866512 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 809866512, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1487124870).

809866512 is an abundant number, since it is smaller than the sum of its proper divisors (2164383228).

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

809866512 is a wasteful number, since it uses less digits than its factorization.

809866512 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 162 (or 134 counting only the distinct ones).

The product of its (nonzero) digits is 207360, while the sum is 45.

The square root of 809866512 is about 28458.1536997747. The cubic root of 809866512 is about 932.1185417812.

The spelling of 809866512 in words is "eight hundred nine million, eight hundred sixty-six thousand, five hundred twelve".