82115640 has 128 divisors (see below), whose sum is σ = 276192000. Its totient is φ = 21700224.

The previous prime is 82115623. The next prime is 82115653. The reversal of 82115640 is 4651128.

82115640 is a `hidden beast` number, since 8 + 2 + 1 + 15 + 640 = 666.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 149847 + ... + 150393.

It is an arithmetic number, because the mean of its divisors is an integer number (2157750).

Almost surely, 2^82115640 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 82115640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (138096000).

82115640 is an abundant number, since it is smaller than the sum of its proper divisors (194076360).

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

82115640 is a wasteful number, since it uses less digits than its factorization.

82115640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 706 (or 696 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 27.

The square root of 82115640 is about 9061.7680394060. The cubic root of 82115640 is about 434.6522786000.

Adding to 82115640 its reverse (4651128), we get a palindrome (86766768).

It can be divided in two parts, 821 and 15640, that added together give a palindrome (16461).

The spelling of 82115640 in words is "eighty-two million, one hundred fifteen thousand, six hundred forty".