8135221 has 2 divisors, whose sum is σ = 8135222. Its totient is φ = 8135220.

The previous prime is 8135203. The next prime is 8135243. The reversal of 8135221 is 1225318.

It is an a-pointer prime, because the next prime (8135243) can be obtained adding 8135221 to its sum of digits (22).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 7896100 + 239121 = 2810^2 + 489^2 .

It is a cyclic number.

It is not a de Polignac number, because 8135221 - 2⁵ = 8135189 is a prime.

It is a zygodrome in base 14.

It is a junction number, because it is equal to n+sod(n) for n = 8135192 and 8135201.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (8135201) 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 as a sum of consecutive naturals, namely, 4067610 + 4067611.

It is an arithmetic number, because the mean of its divisors is an integer number (4067611).

Almost surely, 2^8135221 is an apocalyptic number.

It is an amenable number.

8135221 is a deficient number, since it is larger than the sum of its proper divisors (1).

8135221 is an equidigital number, since it uses as much as digits as its factorization.

8135221 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 480, while the sum is 22.

The square root of 8135221 is about 2852.2308812577. The cubic root of 8135221 is about 201.1205517604.

Subtracting from 8135221 its reverse (1225318), we obtain a triangular number (6909903 = T₃₇₁₇).

The spelling of 8135221 in words is "eight million, one hundred thirty-five thousand, two hundred twenty-one".