84821840 has 80 divisors (see below), whose sum is σ = 213414912. Its totient is φ = 31229952.

The previous prime is 84821837. The next prime is 84821851. The reversal of 84821840 is 4812848.

It is a tau number, because it is divible by the number of its divisors (80).

It is a self number, because there is not a number n which added to its sum of digits gives 84821840.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 63257 + ... + 64583.

Almost surely, 2^84821840 is an apocalyptic number.

84821840 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

84821840 is the 7520-th pentagonal number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 84821840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (106707456).

84821840 is an abundant number, since it is smaller than the sum of its proper divisors (128593072).

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

84821840 is a wasteful number, since it uses less digits than its factorization.

84821840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1404 (or 1398 counting only the distinct ones).

The product of its (nonzero) digits is 16384, while the sum is 35.

The square root of 84821840 is about 9209.8773064575. The cubic root of 84821840 is about 439.3755605078.

The spelling of 84821840 in words is "eighty-four million, eight hundred twenty-one thousand, eight hundred forty".