820851978240 has 624 divisors, whose sum is σ = 3372318313728. Its totient is φ = 187615346688.

The previous prime is 820851978239. The next prime is 820851978253. The reversal of 820851978240 is 42879158028.

820851978240 is a `hidden beast` number, since 8 + 2 + 0 + 8 + 519 + 7 + 82 + 40 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 34824699 + ... + 34848261.

It is an arithmetic number, because the mean of its divisors is an integer number (5404356272).

Almost surely, 2^820851978240 is an apocalyptic number.

820851978240 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 820851978240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1686159156864).

820851978240 is an abundant number, since it is smaller than the sum of its proper divisors (2551466335488).

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

820851978240 is an equidigital number, since it uses as much as digits as its factorization.

820851978240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23614 (or 23580 counting only the distinct ones).

The product of its (nonzero) digits is 2580480, while the sum is 54.

The spelling of 820851978240 in words is "eight hundred twenty billion, eight hundred fifty-one million, nine hundred seventy-eight thousand, two hundred forty".