82178640 has 120 divisors (see below), whose sum is σ = 277625088. Its totient is φ = 21784320.

The previous prime is 82178639. The next prime is 82178647. The reversal of 82178640 is 4687128.

82178640 is a `hidden beast` number, since 8 + 2 + 1 + 7 + 8 + 640 = 666.

It is a tau number, because it is divible by the number of its divisors (120).

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 = 82178595 and 82178604.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (82178647) 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 23 ways as a sum of consecutive naturals, for example, 223737 + ... + 224103.

Almost surely, 2^82178640 is an apocalyptic number.

82178640 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 82178640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (138812544).

82178640 is an abundant number, since it is smaller than the sum of its proper divisors (195446448).

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

82178640 is a wasteful number, since it uses less digits than its factorization.

82178640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 697 (or 688 counting only the distinct ones).

The product of its (nonzero) digits is 21504, while the sum is 36.

The square root of 82178640 is about 9065.2435157584. The cubic root of 82178640 is about 434.7634068157.

The spelling of 82178640 in words is "eighty-two million, one hundred seventy-eight thousand, six hundred forty".