820581984 has 72 divisors (see below), whose sum is σ = 2336803560. Its totient is φ = 273143808.

The previous prime is 820581917. The next prime is 820582043. The reversal of 820581984 is 489185028.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (72).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 266019 + ... + 269085.

It is an arithmetic number, because the mean of its divisors is an integer number (32455605).

Almost surely, 2^820581984 is an apocalyptic number.

It is an amenable number.

820581984 is an abundant number, since it is smaller than the sum of its proper divisors (1516221576).

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

820581984 is a wasteful number, since it uses less digits than its factorization.

820581984 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4012 (or 4001 counting only the distinct ones).

The product of its (nonzero) digits is 184320, while the sum is 45.

The square root of 820581984 is about 28645.8022055588. The cubic root of 820581984 is about 936.2115454351.

The spelling of 820581984 in words is "eight hundred twenty million, five hundred eighty-one thousand, nine hundred eighty-four".