135708521 has 12 divisors (see below), whose sum is σ = 147279132. Its totient is φ = 124989696.

The previous prime is 135708511. The next prime is 135708527. The reversal of 135708521 is 125807531.

It can be written as a sum of positive squares in 6 ways, for example, as 21752896 + 113955625 = 4664^2 + 10675^2 .

It is not a de Polignac number, because 135708521 - 2⁶ = 135708457 is a prime.

It is not an unprimeable number, because it can be changed into a prime (135708527) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 144365 + ... + 145301.

It is an arithmetic number, because the mean of its divisors is an integer number (12273261).

Almost surely, 2^135708521 is an apocalyptic number.

It is an amenable number.

135708521 is a deficient number, since it is larger than the sum of its proper divisors (11570611).

135708521 is an equidigital number, since it uses as much as digits as its factorization.

135708521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1820 (or 1807 counting only the distinct ones).

The product of its (nonzero) digits is 8400, while the sum is 32.

The square root of 135708521 is about 11649.4000274692. The cubic root of 135708521 is about 513.8886658489. Note that the first 3 decimals are identical.

The spelling of 135708521 in words is "one hundred thirty-five million, seven hundred eight thousand, five hundred twenty-one".