820109515680 has 576 divisors, whose sum is σ = 3625758339840. Its totient is φ = 163926540288.

The previous prime is 820109515639. The next prime is 820109515681. The reversal of 820109515680 is 86515901028.

It is a happy number.

820109515680 is a `hidden beast` number, since 8 + 20 + 10 + 9 + 51 + 568 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is not an unprimeable number, because it can be changed into a prime (820109515681) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 2325064 + ... + 2654456.

It is an arithmetic number, because the mean of its divisors is an integer number (6294719340).

Almost surely, 2^820109515680 is an apocalyptic number.

820109515680 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 820109515680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1812879169920).

820109515680 is an abundant number, since it is smaller than the sum of its proper divisors (2805648824160).

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

820109515680 is a wasteful number, since it uses less digits than its factorization.

820109515680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 329453 (or 329442 counting only the distinct ones).

The product of its (nonzero) digits is 172800, while the sum is 45.

The spelling of 820109515680 in words is "eight hundred twenty billion, one hundred nine million, five hundred fifteen thousand, six hundred eighty".