61811181 has 18 divisors (see below), whose sum is σ = 92721902. Its totient is φ = 41203080.

The previous prime is 61811159. The next prime is 61811219. The reversal of 61811181 is 18111816.

It can be written as a sum of positive squares in only one way, i.e., 48525156 + 13286025 = 6966^2 + 3645^2 .

It is not a de Polignac number, because 61811181 - 2¹⁰ = 61810157 is a prime.

It is a super-2 number, since 2×61811181² = 7641244193229522, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

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 (61811111) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 1851 + ... + 11271.

Almost surely, 2^61811181 is an apocalyptic number.

It is an amenable number.

61811181 is a deficient number, since it is larger than the sum of its proper divisors (30910721).

61811181 is an frugal number, since it uses more digits than its factorization.

61811181 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9445 (or 9424 counting only the distinct ones).

The product of its digits is 384, while the sum is 27.

The square root of 61811181 is about 7862.0087127909. The cubic root of 61811181 is about 395.3869646919.

Adding to 61811181 its reverse (18111816), we get a palindrome (79922997).

The spelling of 61811181 in words is "sixty-one million, eight hundred eleven thousand, one hundred eighty-one".