82081621 has 2 divisors, whose sum is σ = 82081622. Its totient is φ = 82081620.

The previous prime is 82081613. The next prime is 82081663. The reversal of 82081621 is 12618028.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 75881521 + 6200100 = 8711^2 + 2490^2 .

It is a cyclic number.

It is not a de Polignac number, because 82081621 - 2³ = 82081613 is a prime.

It is a super-3 number, since 3×82081621³ (a number of 25 digits) contains 333 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 82081621.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (82081721) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 41040810 + 41040811.

It is an arithmetic number, because the mean of its divisors is an integer number (41040811).

Almost surely, 2^82081621 is an apocalyptic number.

It is an amenable number.

82081621 is a deficient number, since it is larger than the sum of its proper divisors (1).

82081621 is an equidigital number, since it uses as much as digits as its factorization.

82081621 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1536, while the sum is 28.

The square root of 82081621 is about 9059.8907830062. The cubic root of 82081621 is about 434.5922474933.

Adding to 82081621 its reverse (12618028), we get a palindrome (94699649).

The spelling of 82081621 in words is "eighty-two million, eighty-one thousand, six hundred twenty-one".