851864821 has 8 divisors (see below), whose sum is σ = 892396800. Its totient is φ = 812076720.

The previous prime is 851864807. The next prime is 851864861. The reversal of 851864821 is 128468158.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 851864821 - 2⁵ = 851864789 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (851864861) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 183625 + ... + 188206.

It is an arithmetic number, because the mean of its divisors is an integer number (111549600).

Almost surely, 2^851864821 is an apocalyptic number.

It is an amenable number.

851864821 is a deficient number, since it is larger than the sum of its proper divisors (40531979).

851864821 is a wasteful number, since it uses less digits than its factorization.

851864821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 371939.

The product of its digits is 122880, while the sum is 43.

The square root of 851864821 is about 29186.7233686825. The cubic root of 851864821 is about 947.9604706912.

The spelling of 851864821 in words is "eight hundred fifty-one million, eight hundred sixty-four thousand, eight hundred twenty-one".