856489984 has 68 divisors (see below), whose sum is σ = 1958725024. Its totient is φ = 366870528.

The previous prime is 856489951. The next prime is 856490003. The reversal of 856489984 is 489984658.

It is a Smith number, since the sum of its digits (61) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 457819 + ... + 459685.

Almost surely, 2^856489984 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 856489984, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (979362512).

856489984 is an abundant number, since it is smaller than the sum of its proper divisors (1102235040).

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

856489984 is an frugal number, since it uses more digits than its factorization.

856489984 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1906 (or 1876 counting only the distinct ones).

The product of its digits is 19906560, while the sum is 61.

The square root of 856489984 is about 29265.8501328767. The cubic root of 856489984 is about 949.6730117486.

The spelling of 856489984 in words is "eight hundred fifty-six million, four hundred eighty-nine thousand, nine hundred eighty-four".