82117720 has 16 divisors (see below), whose sum is σ = 184764960. Its totient is φ = 32847072.

The previous prime is 82117703. The next prime is 82117727. The reversal of 82117720 is 2771128.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (82117727) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1026432 + ... + 1026511.

It is an arithmetic number, because the mean of its divisors is an integer number (11547810).

Almost surely, 2^82117720 is an apocalyptic number.

It is an amenable number.

82117720 is an abundant number, since it is smaller than the sum of its proper divisors (102647240).

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

82117720 is a wasteful number, since it uses less digits than its factorization.

82117720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2052954 (or 2052950 counting only the distinct ones).

The product of its (nonzero) digits is 1568, while the sum is 28.

The square root of 82117720 is about 9061.8828065695. The cubic root of 82117720 is about 434.6559485022.

Adding to 82117720 its reverse (2771128), we get a palindrome (84888848).

It can be divided in two parts, 8211 and 7720, that added together give a triangular number (15931 = T₁₇₈).

The spelling of 82117720 in words is "eighty-two million, one hundred seventeen thousand, seven hundred twenty".