82101821 has 8 divisors (see below), whose sum is σ = 82816344. Its totient is φ = 81390400.

The previous prime is 82101797. The next prime is 82101829. The reversal of 82101821 is 12810128.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 70744921 + 11356900 = 8411^2 + 3370^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 82101821 - 2¹⁰ = 82100797 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (82101829) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 116771 + ... + 117471.

It is an arithmetic number, because the mean of its divisors is an integer number (10352043).

Almost surely, 2^82101821 is an apocalyptic number.

It is an amenable number.

82101821 is a deficient number, since it is larger than the sum of its proper divisors (714523).

82101821 is a wasteful number, since it uses less digits than its factorization.

82101821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1551.

The product of its (nonzero) digits is 256, while the sum is 23.

The square root of 82101821 is about 9061.0055181530. The cubic root of 82101821 is about 434.6278951135.

Adding to 82101821 its reverse (12810128), we get a palindrome (94911949).

The spelling of 82101821 in words is "eighty-two million, one hundred one thousand, eight hundred twenty-one".