855636820 has 12 divisors (see below), whose sum is σ = 1796837364. Its totient is φ = 342254720.

The previous prime is 855636773. The next prime is 855636827. The reversal of 855636820 is 28636558.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 626901444 + 228735376 = 25038^2 + 15124^2 .

It is a super-2 number, since 2×855636820² = 1464228735479424800, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (855636827) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 21390901 + ... + 21390940.

It is an arithmetic number, because the mean of its divisors is an integer number (149736447).

Almost surely, 2^855636820 is an apocalyptic number.

It is an amenable number.

855636820 is an abundant number, since it is smaller than the sum of its proper divisors (941200544).

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

855636820 is a wasteful number, since it uses less digits than its factorization.

855636820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 42781850 (or 42781848 counting only the distinct ones).

The product of its (nonzero) digits is 345600, while the sum is 43.

The square root of 855636820 is about 29251.2703997621. The cubic root of 855636820 is about 949.3575785984.

The spelling of 855636820 in words is "eight hundred fifty-five million, six hundred thirty-six thousand, eight hundred twenty".