82172581 has 2 divisors, whose sum is σ = 82172582. Its totient is φ = 82172580.

The previous prime is 82172533. The next prime is 82172609. The reversal of 82172581 is 18527128.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 79816356 + 2356225 = 8934^2 + 1535^2 .

It is a cyclic number.

It is not a de Polignac number, because 82172581 - 2¹³ = 82164389 is a prime.

It is a super-2 number, since 2×82172581² = 13504666136403122, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (82172521) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 41086290 + 41086291.

It is an arithmetic number, because the mean of its divisors is an integer number (41086291).

Almost surely, 2^82172581 is an apocalyptic number.

It is an amenable number.

82172581 is a deficient number, since it is larger than the sum of its proper divisors (1).

82172581 is an equidigital number, since it uses as much as digits as its factorization.

82172581 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 8960, while the sum is 34.

The square root of 82172581 is about 9064.9093211129. The cubic root of 82172581 is about 434.7527215727.

The spelling of 82172581 in words is "eighty-two million, one hundred seventy-two thousand, five hundred eighty-one".