135851521 has 4 divisors (see below), whose sum is σ = 146301652. Its totient is φ = 125401392.

The previous prime is 135851509. The next prime is 135851533. The reversal of 135851521 is 125158531.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 125158531 = 37 ⋅3382663.

It is an interprime number because it is at equal distance from previous prime (135851509) and next prime (135851533).

It can be written as a sum of positive squares in 2 ways, for example, as 8410000 + 127441521 = 2900^2 + 11289^2 .

It is a cyclic number.

It is not a de Polignac number, because 135851521 - 2¹¹ = 135849473 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (135851581) 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, 5225046 + ... + 5225071.

It is an arithmetic number, because the mean of its divisors is an integer number (36575413).

Almost surely, 2^135851521 is an apocalyptic number.

It is an amenable number.

135851521 is a deficient number, since it is larger than the sum of its proper divisors (10450131).

135851521 is a wasteful number, since it uses less digits than its factorization.

135851521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10450130.

The product of its digits is 6000, while the sum is 31.

The square root of 135851521 is about 11655.5360666080. The cubic root of 135851521 is about 514.0691022781.

The spelling of 135851521 in words is "one hundred thirty-five million, eight hundred fifty-one thousand, five hundred twenty-one".