82158121 has 2 divisors, whose sum is σ = 82158122. Its totient is φ = 82158120.

The previous prime is 82158113. The next prime is 82158143. The reversal of 82158121 is 12185128.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 82156096 + 2025 = 9064^2 + 45^2 .

It is a cyclic number.

It is not a de Polignac number, because 82158121 - 2³ = 82158113 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 82158121.

It is not a weakly prime, because it can be changed into another prime (82158151) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 41079060 + 41079061.

It is an arithmetic number, because the mean of its divisors is an integer number (41079061).

Almost surely, 2^82158121 is an apocalyptic number.

It is an amenable number.

82158121 is a deficient number, since it is larger than the sum of its proper divisors (1).

82158121 is an equidigital number, since it uses as much as digits as its factorization.

82158121 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1280, while the sum is 28.

The square root of 82158121 is about 9064.1117049604. Note that the first 3 decimals coincide. The cubic root of 82158121 is about 434.7272187709.

It can be divided in two parts, 82 and 158121, that added together give a triangular number (158203 = T₅₆₂).

The spelling of 82158121 in words is "eighty-two million, one hundred fifty-eight thousand, one hundred twenty-one".