82639440 has 280 divisors, whose sum is σ = 313078920. Its totient is φ = 20155392.

The previous prime is 82639433. The next prime is 82639511. The reversal of 82639440 is 4493628.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 4210704 + 78428736 = 2052^2 + 8856^2 .

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

It is a junction number, because it is equal to n+sod(n) for n = 82639395 and 82639404.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 55 ways as a sum of consecutive naturals, for example, 758106 + ... + 758214.

It is an arithmetic number, because the mean of its divisors is an integer number (1118139).

Almost surely, 2^82639440 is an apocalyptic number.

82639440 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 82639440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (156539460).

82639440 is an abundant number, since it is smaller than the sum of its proper divisors (230439480).

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

82639440 is a wasteful number, since it uses less digits than its factorization.

82639440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 153 (or 132 counting only the distinct ones).

The product of its (nonzero) digits is 41472, while the sum is 36.

The square root of 82639440 is about 9090.6237409762. The cubic root of 82639440 is about 435.5745084461.

The spelling of 82639440 in words is "eighty-two million, six hundred thirty-nine thousand, four hundred forty".