856557918720 has 800 divisors, whose sum is σ = 3658779894528. Its totient is φ = 187264991232.

The previous prime is 856557918677. The next prime is 856557918721. The reversal of 856557918720 is 27819755658.

856557918720 is a `hidden beast` number, since 8 + 5 + 6 + 557 + 9 + 1 + 8 + 72 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (63).

It is not an unprimeable number, because it can be changed into a prime (856557918721) by changing a digit.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 33372132 + ... + 33397788.

Almost surely, 2^856557918720 is an apocalyptic number.

856557918720 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 856557918720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1829389947264).

856557918720 is an abundant number, since it is smaller than the sum of its proper divisors (2802221975808).

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

856557918720 is a wasteful number, since it uses less digits than its factorization.

856557918720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25722 (or 25697 counting only the distinct ones).

The product of its (nonzero) digits is 42336000, while the sum is 63.

The spelling of 856557918720 in words is "eight hundred fifty-six billion, five hundred fifty-seven million, nine hundred eighteen thousand, seven hundred twenty".