135251221 has 12 divisors (see below), whose sum is σ = 158896620. Its totient is φ = 114777600.

The previous prime is 135251219. The next prime is 135251267. The reversal of 135251221 is 122152531.

It can be written as a sum of positive squares in 2 ways, for example, as 103734225 + 31516996 = 10185^2 + 5614^2 .

It is not a de Polignac number, because 135251221 - 2¹ = 135251219 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 135251192 and 135251201.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (135251321) 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, 8716 + ... + 18613.

It is an arithmetic number, because the mean of its divisors is an integer number (13241385).

Almost surely, 2^135251221 is an apocalyptic number.

It is an amenable number.

135251221 is a deficient number, since it is larger than the sum of its proper divisors (23645399).

135251221 is a wasteful number, since it uses less digits than its factorization.

135251221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27444 (or 27437 counting only the distinct ones).

The product of its digits is 600, while the sum is 22.

The square root of 135251221 is about 11629.7558443847. The cubic root of 135251221 is about 513.3107956129.

The spelling of 135251221 in words is "one hundred thirty-five million, two hundred fifty-one thousand, two hundred twenty-one".