135815321 has 2 divisors, whose sum is σ = 135815322. Its totient is φ = 135815320.

The previous prime is 135815291. The next prime is 135815333. The reversal of 135815321 is 123518531.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 134815321 + 1000000 = 11611^2 + 1000^2 .

It is an emirp because it is prime and its reverse (123518531) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 135815321 - 2⁶ = 135815257 is a prime.

It is not a weakly prime, because it can be changed into another prime (135815221) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 67907660 + 67907661.

It is an arithmetic number, because the mean of its divisors is an integer number (67907661).

Almost surely, 2^135815321 is an apocalyptic number.

It is an amenable number.

135815321 is a deficient number, since it is larger than the sum of its proper divisors (1).

135815321 is an equidigital number, since it uses as much as digits as its factorization.

135815321 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3600, while the sum is 29.

The square root of 135815321 is about 11653.9830530167. The cubic root of 135815321 is about 514.0234373381.

The spelling of 135815321 in words is "one hundred thirty-five million, eight hundred fifteen thousand, three hundred twenty-one".