36138581 has 4 divisors (see below), whose sum is σ = 36152064. Its totient is φ = 36125100.

The previous prime is 36138563. The next prime is 36138593. The reversal of 36138581 is 18583163.

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 a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 18583163 = 97 ⋅191579.

It is a cyclic number.

It is not a de Polignac number, because 36138581 - 2⁶ = 36138517 is a prime.

It is a super-2 number, since 2×36138581² = 2611994073387122, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (36138881) 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, 1205 + ... + 8586.

It is an arithmetic number, because the mean of its divisors is an integer number (9038016).

Almost surely, 2^36138581 is an apocalyptic number.

It is an amenable number.

36138581 is a deficient number, since it is larger than the sum of its proper divisors (13483).

36138581 is an equidigital number, since it uses as much as digits as its factorization.

36138581 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13482.

The product of its digits is 17280, while the sum is 35.

The square root of 36138581 is about 6011.5373241792. The cubic root of 36138581 is about 330.6158716300.

The spelling of 36138581 in words is "thirty-six million, one hundred thirty-eight thousand, five hundred eighty-one".