820565136 has 60 divisors (see below), whose sum is σ = 2314026000. Its totient is φ = 271427520.

The previous prime is 820565111. The next prime is 820565143. The reversal of 820565136 is 631565028.

820565136 is a `hidden beast` number, since 82 + 0 + 565 + 13 + 6 = 666.

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

It is a self number, because there is not a number n which added to its sum of digits gives 820565136.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2886 + ... + 40613.

It is an arithmetic number, because the mean of its divisors is an integer number (38567100).

Almost surely, 2^820565136 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 820565136, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1157013000).

820565136 is an abundant number, since it is smaller than the sum of its proper divisors (1493460864).

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

820565136 is a wasteful number, since it uses less digits than its factorization.

820565136 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 43644 (or 43635 counting only the distinct ones).

The product of its (nonzero) digits is 43200, while the sum is 36.

The square root of 820565136 is about 28645.5081295480. The cubic root of 820565136 is about 936.2051380314.

The spelling of 820565136 in words is "eight hundred twenty million, five hundred sixty-five thousand, one hundred thirty-six".