135217581 has 8 divisors (see below), whose sum is σ = 180344640. Its totient is φ = 90117792.

The previous prime is 135217571. The next prime is 135217597. The reversal of 135217581 is 185712531.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 135217581 - 2¹⁷ = 135086509 is a prime.

It is a super-2 number, since 2×135217581² = 36567588422983122, which contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (135217501) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12921 + ... + 20913.

It is an arithmetic number, because the mean of its divisors is an integer number (22543080).

Almost surely, 2^135217581 is an apocalyptic number.

It is an amenable number.

135217581 is a deficient number, since it is larger than the sum of its proper divisors (45127059).

135217581 is an equidigital number, since it uses as much as digits as its factorization.

135217581 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13635.

The product of its digits is 8400, while the sum is 33.

The square root of 135217581 is about 11628.3094644063. The cubic root of 135217581 is about 513.2682347969.

The spelling of 135217581 in words is "one hundred thirty-five million, two hundred seventeen thousand, five hundred eighty-one".