82129840 has 80 divisors (see below), whose sum is σ = 207361728. Its totient is φ = 30071808.

The previous prime is 82129793. The next prime is 82129841. The reversal of 82129840 is 4892128.

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

It is a junction number, because it is equal to n+sod(n) for n = 82129796 and 82129805.

It is not an unprimeable number, because it can be changed into a prime (82129841) by changing a digit.

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, 163029 + ... + 163531.

Almost surely, 2^82129840 is an apocalyptic number.

82129840 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 82129840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (103680864).

82129840 is an abundant number, since it is smaller than the sum of its proper divisors (125231888).

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

82129840 is a wasteful number, since it uses less digits than its factorization.

82129840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 686 (or 680 counting only the distinct ones).

The product of its (nonzero) digits is 9216, while the sum is 34.

The square root of 82129840 is about 9062.5515170950. The cubic root of 82129840 is about 434.6773315076.

The spelling of 82129840 in words is "eighty-two million, one hundred twenty-nine thousand, eight hundred forty".