861275856 has 80 divisors (see below), whose sum is σ = 2549043200. Its totient is φ = 245476224.

The previous prime is 861275837. The next prime is 861275887. The reversal of 861275856 is 658572168.

It is a super-2 number, since 2×861275856² = 1483592200257065472, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (48).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 144585 + ... + 150423.

It is an arithmetic number, because the mean of its divisors is an integer number (31863040).

Almost surely, 2^861275856 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 861275856, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1274521600).

861275856 is an abundant number, since it is smaller than the sum of its proper divisors (1687767344).

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

861275856 is a wasteful number, since it uses less digits than its factorization.

861275856 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6296 (or 6290 counting only the distinct ones).

The product of its digits is 806400, while the sum is 48.

The square root of 861275856 is about 29347.5016994633. The cubic root of 861275856 is about 951.4385798389.

The spelling of 861275856 in words is "eight hundred sixty-one million, two hundred seventy-five thousand, eight hundred fifty-six".