855721660 has 48 divisors (see below), whose sum is σ = 1845299232. Its totient is φ = 333132800.

The previous prime is 855721637. The next prime is 855721679. The reversal of 855721660 is 66127558.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 426219 + ... + 428221.

It is an arithmetic number, because the mean of its divisors is an integer number (38443734).

Almost surely, 2^855721660 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 855721660, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (922649616).

855721660 is an abundant number, since it is smaller than the sum of its proper divisors (989577572).

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

855721660 is a wasteful number, since it uses less digits than its factorization.

855721660 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2574 (or 2572 counting only the distinct ones).

The product of its (nonzero) digits is 100800, while the sum is 40.

The square root of 855721660 is about 29252.7205572405. The cubic root of 855721660 is about 949.3889551642.

The spelling of 855721660 in words is "eight hundred fifty-five million, seven hundred twenty-one thousand, six hundred sixty".