851521860 has 144 divisors (see below), whose sum is σ = 3107395200. Its totient is φ = 184384512.

The previous prime is 851521831. The next prime is 851521861. The reversal of 851521860 is 68125158.

851521860 is a `hidden beast` number, since 8 + 51 + 521 + 86 + 0 = 666.

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

It is not an unprimeable number, because it can be changed into a prime (851521861) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 6156 + ... + 41724.

Almost surely, 2^851521860 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 851521860, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1553697600).

851521860 is an abundant number, since it is smaller than the sum of its proper divisors (2255873340).

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

851521860 is a wasteful number, since it uses less digits than its factorization.

851521860 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 35610 (or 35605 counting only the distinct ones).

The product of its (nonzero) digits is 19200, while the sum is 36.

The square root of 851521860 is about 29180.8474859796. The cubic root of 851521860 is about 947.8332372370.

The spelling of 851521860 in words is "eight hundred fifty-one million, five hundred twenty-one thousand, eight hundred sixty".