820616580 has 144 divisors (see below), whose sum is σ = 2885186304. Its totient is φ = 184907520.

The previous prime is 820616561. The next prime is 820616581. The reversal of 820616580 is 85616028.

It is a happy number.

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

It is not an unprimeable number, because it can be changed into a prime (820616581) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 84874 + ... + 94046.

It is an arithmetic number, because the mean of its divisors is an integer number (20036016).

Almost surely, 2^820616580 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 820616580, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1442593152).

820616580 is an abundant number, since it is smaller than the sum of its proper divisors (2064569724).

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

820616580 is a wasteful number, since it uses less digits than its factorization.

820616580 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9266 (or 9261 counting only the distinct ones).

The product of its (nonzero) digits is 23040, while the sum is 36.

The square root of 820616580 is about 28646.4060573050. The cubic root of 820616580 is about 936.2247022433.

The spelling of 820616580 in words is "eight hundred twenty million, six hundred sixteen thousand, five hundred eighty".