856880640 has 960 divisors, whose sum is σ = 4030456320. Its totient is φ = 170311680.

The previous prime is 856880599. The next prime is 856880653. The reversal of 856880640 is 46088658.

856880640 is a `hidden beast` number, since 8 + 568 + 80 + 6 + 4 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (960).

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 37255669 + ... + 37255691.

It is an arithmetic number, because the mean of its divisors is an integer number (4198392).

Almost surely, 2^856880640 is an apocalyptic number.

856880640 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 856880640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2015228160).

856880640 is an abundant number, since it is smaller than the sum of its proper divisors (3173575680).

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

856880640 is a wasteful number, since it uses less digits than its factorization.

856880640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 80 (or 51 counting only the distinct ones).

The product of its (nonzero) digits is 368640, while the sum is 45.

The square root of 856880640 is about 29272.5236356553. The cubic root of 856880640 is about 949.8173757910.

The spelling of 856880640 in words is "eight hundred fifty-six million, eight hundred eighty thousand, six hundred forty".