850513644 has 72 divisors (see below), whose sum is σ = 2336122880. Its totient is φ = 259912800.

The previous prime is 850513633. The next prime is 850513679. The reversal of 850513644 is 446315058.

It is a happy number.

850513644 is a `hidden beast` number, since 8 + 5 + 0 + 5 + 1 + 3 + 644 = 666.

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 = 850513599 and 850513608.

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 23 ways as a sum of consecutive naturals, for example, 1149 + ... + 41259.

Almost surely, 2^850513644 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 850513644, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1168061440).

850513644 is an abundant number, since it is smaller than the sum of its proper divisors (1485609236).

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

850513644 is a wasteful number, since it uses less digits than its factorization.

850513644 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40171 (or 40166 counting only the distinct ones).

The product of its (nonzero) digits is 57600, while the sum is 36.

The square root of 850513644 is about 29163.5670657758. The cubic root of 850513644 is about 947.4590060770.

The spelling of 850513644 in words is "eight hundred fifty million, five hundred thirteen thousand, six hundred forty-four".