136520381 has 4 divisors (see below), whose sum is σ = 136550172. Its totient is φ = 136490592.

The previous prime is 136520369. The next prime is 136520401. The reversal of 136520381 is 183025631.

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

It can be written as a sum of positive squares in 2 ways, for example, as 34692100 + 101828281 = 5890^2 + 10091^2 .

It is a cyclic number.

It is not a de Polignac number, because 136520381 - 2⁶ = 136520317 is a prime.

It is a super-3 number, since 3×136520381³ (a number of 25 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (136523381) 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, 6410 + ... + 17723.

It is an arithmetic number, because the mean of its divisors is an integer number (34137543).

Almost surely, 2^136520381 is an apocalyptic number.

It is an amenable number.

136520381 is a deficient number, since it is larger than the sum of its proper divisors (29791).

136520381 is an equidigital number, since it uses as much as digits as its factorization.

136520381 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29790.

The product of its (nonzero) digits is 4320, while the sum is 29.

The square root of 136520381 is about 11684.1936392718. The cubic root of 136520381 is about 514.9113882795.

The spelling of 136520381 in words is "one hundred thirty-six million, five hundred twenty thousand, three hundred eighty-one".