856540440 has 256 divisors, whose sum is σ = 3290803200. Its totient is φ = 194116608.

The previous prime is 856540439. The next prime is 856540441. The reversal of 856540440 is 44045658.

It is an interprime number because it is at equal distance from previous prime (856540439) and next prime (856540441).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 856540395 and 856540404.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (856540441) by changing a digit.

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 63 ways as a sum of consecutive naturals, for example, 1035307 + ... + 1036133.

It is an arithmetic number, because the mean of its divisors is an integer number (12854700).

Almost surely, 2^856540440 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 856540440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1645401600).

856540440 is an abundant number, since it is smaller than the sum of its proper divisors (2434262760).

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

856540440 is a wasteful number, since it uses less digits than its factorization.

856540440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 991 (or 981 counting only the distinct ones).

The product of its (nonzero) digits is 76800, while the sum is 36.

The square root of 856540440 is about 29266.7121487877. The cubic root of 856540440 is about 949.6916598594.

The spelling of 856540440 in words is "eight hundred fifty-six million, five hundred forty thousand, four hundred forty".