82097821 has 4 divisors (see below), whose sum is σ = 88413052. Its totient is φ = 75782592.

The previous prime is 82097801. The next prime is 82097837. The reversal of 82097821 is 12879028.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 21724921 + 60372900 = 4661^2 + 7770^2 .

It is a cyclic number.

It is not a de Polignac number, because 82097821 - 2⁵ = 82097789 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (82097801) 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, 3157596 + ... + 3157621.

It is an arithmetic number, because the mean of its divisors is an integer number (22103263).

Almost surely, 2^82097821 is an apocalyptic number.

It is an amenable number.

82097821 is a deficient number, since it is larger than the sum of its proper divisors (6315231).

82097821 is a wasteful number, since it uses less digits than its factorization.

82097821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6315230.

The product of its (nonzero) digits is 16128, while the sum is 37.

The square root of 82097821 is about 9060.7847894098. The cubic root of 82097821 is about 434.6208366431.

The spelling of 82097821 in words is "eighty-two million, ninety-seven thousand, eight hundred twenty-one".