135510821 has 2 divisors, whose sum is σ = 135510822. Its totient is φ = 135510820.

The previous prime is 135510811. The next prime is 135510839. The reversal of 135510821 is 128015531.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 69722500 + 65788321 = 8350^2 + 8111^2 .

It is a cyclic number.

It is not a de Polignac number, because 135510821 - 2¹⁸ = 135248677 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (135510811) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 67755410 + 67755411.

It is an arithmetic number, because the mean of its divisors is an integer number (67755411).

Almost surely, 2^135510821 is an apocalyptic number.

It is an amenable number.

135510821 is a deficient number, since it is larger than the sum of its proper divisors (1).

135510821 is an equidigital number, since it uses as much as digits as its factorization.

135510821 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1200, while the sum is 26.

The square root of 135510821 is about 11640.9115192926. The cubic root of 135510821 is about 513.6390004549.

The spelling of 135510821 in words is "one hundred thirty-five million, five hundred ten thousand, eight hundred twenty-one".