82921680 has 180 divisors, whose sum is σ = 290754828. Its totient is φ = 21166080.

The previous prime is 82921669. The next prime is 82921687. The reversal of 82921680 is 8612928.

It can be written as a sum of positive squares in 6 ways, for example, as 1272384 + 81649296 = 1128^2 + 9036^2 .

It is a tau number, because it is divible by the number of its divisors (180).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (82921687) by changing a digit.

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 35 ways as a sum of consecutive naturals, for example, 1564534 + ... + 1564586.

Almost surely, 2^82921680 is an apocalyptic number.

82921680 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 82921680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (145377414).

82921680 is an abundant number, since it is smaller than the sum of its proper divisors (207833148).

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

82921680 is a wasteful number, since it uses less digits than its factorization.

82921680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 166 (or 104 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 36.

The square root of 82921680 is about 9106.1341962438. The cubic root of 82921680 is about 436.0698202020.

The spelling of 82921680 in words is "eighty-two million, nine hundred twenty-one thousand, six hundred eighty".