135728251 has 4 divisors (see below), whose sum is σ = 136244592. Its totient is φ = 135211912.

The previous prime is 135728249. The next prime is 135728269. The reversal of 135728251 is 152827531.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 152827531 = 181 ⋅844351.

It is a cyclic number.

It is not a de Polignac number, because 135728251 - 2¹ = 135728249 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (135728231) 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 in 3 ways as a sum of consecutive naturals, for example, 257776 + ... + 258301.

It is an arithmetic number, because the mean of its divisors is an integer number (34061148).

Almost surely, 2^135728251 is an apocalyptic number.

135728251 is a deficient number, since it is larger than the sum of its proper divisors (516341).

135728251 is an equidigital number, since it uses as much as digits as its factorization.

135728251 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 516340.

The product of its digits is 16800, while the sum is 34.

The square root of 135728251 is about 11650.2468214197. The cubic root of 135728251 is about 513.9135685644.

The spelling of 135728251 in words is "one hundred thirty-five million, seven hundred twenty-eight thousand, two hundred fifty-one".