82107721 has 16 divisors (see below), whose sum is σ = 88099200. Its totient is φ = 76301568.

The previous prime is 82107719. The next prime is 82107749. The reversal of 82107721 is 12770128.

It is not a de Polignac number, because 82107721 - 2¹ = 82107719 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 82107721.

It is not an unprimeable number, because it can be changed into a prime (82102721) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 358435 + ... + 358663.

It is an arithmetic number, because the mean of its divisors is an integer number (5506200).

Almost surely, 2^82107721 is an apocalyptic number.

It is an amenable number.

82107721 is a deficient number, since it is larger than the sum of its proper divisors (5991479).

82107721 is a wasteful number, since it uses less digits than its factorization.

82107721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 528.

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

The square root of 82107721 is about 9061.3310832350. The cubic root of 82107721 is about 434.6383059388.

Adding to 82107721 its reverse (12770128), we get a palindrome (94877849).

It can be divided in two parts, 82107 and 721, that added together give a palindrome (82828).

The spelling of 82107721 in words is "eighty-two million, one hundred seven thousand, seven hundred twenty-one".