61135581 has 24 divisors (see below), whose sum is σ = 90680160. Its totient is φ = 36593856.

The previous prime is 61135577. The next prime is 61135583. The reversal of 61135581 is 18553116.

It is not a de Polignac number, because 61135581 - 2² = 61135577 is a prime.

It is a super-2 number, since 2×61135581² = 7475118528415122, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61135583) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 17130 + ... + 20388.

It is an arithmetic number, because the mean of its divisors is an integer number (3778340).

Almost surely, 2^61135581 is an apocalyptic number.

It is an amenable number.

61135581 is a deficient number, since it is larger than the sum of its proper divisors (29544579).

61135581 is a wasteful number, since it uses less digits than its factorization.

61135581 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3325 (or 3312 counting only the distinct ones).

The product of its digits is 3600, while the sum is 30.

The square root of 61135581 is about 7818.9245424163. The cubic root of 61135581 is about 393.9411496184.

Adding to 61135581 its reverse (18553116), we get a palindrome (79688697).

It can be divided in two parts, 61135 and 581, that added together give a palindrome (61716).

The spelling of 61135581 in words is "sixty-one million, one hundred thirty-five thousand, five hundred eighty-one".