82215521 has 4 divisors (see below), whose sum is σ = 82483632. Its totient is φ = 81947412.

The previous prime is 82215487. The next prime is 82215563. The reversal of 82215521 is 12551228.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 82215521 - 2²² = 78021217 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (82215821) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 133595 + ... + 134208.

It is an arithmetic number, because the mean of its divisors is an integer number (20620908).

Almost surely, 2^82215521 is an apocalyptic number.

It is an amenable number.

82215521 is a deficient number, since it is larger than the sum of its proper divisors (268111).

82215521 is a wasteful number, since it uses less digits than its factorization.

82215521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 268110.

The product of its digits is 1600, while the sum is 26.

The square root of 82215521 is about 9067.2774855521. The cubic root of 82215521 is about 434.8284363299.

Adding to 82215521 its reverse (12551228), we get a palindrome (94766749).

The spelling of 82215521 in words is "eighty-two million, two hundred fifteen thousand, five hundred twenty-one".