135213251 has 4 divisors (see below), whose sum is σ = 141092112. Its totient is φ = 129334392.

The previous prime is 135213241. The next prime is 135213259. The reversal of 135213251 is 152312531.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-135213251 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (23), and also a Moran number because the ratio is a prime number: 5878837 = 135213251 / (1 + 3 + 5 + 2 + 1 + 3 + 2 + 5 + 1).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (135213259) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2939396 + ... + 2939441.

It is an arithmetic number, because the mean of its divisors is an integer number (35273028).

Almost surely, 2^135213251 is an apocalyptic number.

135213251 is a deficient number, since it is larger than the sum of its proper divisors (5878861).

135213251 is an equidigital number, since it uses as much as digits as its factorization.

135213251 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5878860.

The product of its digits is 900, while the sum is 23.

The square root of 135213251 is about 11628.1232793603. The cubic root of 135213251 is about 513.2627560340.

Adding to 135213251 its reverse (152312531), we get a palindrome (287525782).

The spelling of 135213251 in words is "one hundred thirty-five million, two hundred thirteen thousand, two hundred fifty-one".