856913820 has 96 divisors (see below), whose sum is σ = 2759167488. Its totient is φ = 194648832.

The previous prime is 856913809. The next prime is 856913861. The reversal of 856913820 is 28319658.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 62202 + ... + 74718.

It is an arithmetic number, because the mean of its divisors is an integer number (28741328).

Almost surely, 2^856913820 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 856913820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1379583744).

856913820 is an abundant number, since it is smaller than the sum of its proper divisors (1902253668).

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

856913820 is a wasteful number, since it uses less digits than its factorization.

856913820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12699 (or 12697 counting only the distinct ones).

The product of its (nonzero) digits is 103680, while the sum is 42.

The square root of 856913820 is about 29273.0903732421. The cubic root of 856913820 is about 949.8296351934.

The spelling of 856913820 in words is "eight hundred fifty-six million, nine hundred thirteen thousand, eight hundred twenty".