135120257 has 4 divisors (see below), whose sum is σ = 136830720. Its totient is φ = 133409796.

The previous prime is 135120247. The next prime is 135120259. The reversal of 135120257 is 752021531.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 752021531 = 16487 ⋅45613.

It is a cyclic number.

It is not a de Polignac number, because 135120257 - 2¹⁰ = 135119233 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (135120259) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 855113 + ... + 855270.

It is an arithmetic number, because the mean of its divisors is an integer number (34207680).

Almost surely, 2^135120257 is an apocalyptic number.

It is an amenable number.

135120257 is a deficient number, since it is larger than the sum of its proper divisors (1710463).

135120257 is an equidigital number, since it uses as much as digits as its factorization.

135120257 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1710462.

The product of its (nonzero) digits is 2100, while the sum is 26.

The square root of 135120257 is about 11624.1239239781. The cubic root of 135120257 is about 513.1450621865.

Adding to 135120257 its reverse (752021531), we get a palindrome (887141788).

The spelling of 135120257 in words is "one hundred thirty-five million, one hundred twenty thousand, two hundred fifty-seven".