61218081 has 12 divisors (see below), whose sum is σ = 88540452. Its totient is φ = 40759296.

The previous prime is 61218077. The next prime is 61218083. The reversal of 61218081 is 18081216.

It can be written as a sum of positive squares in 2 ways, for example, as 59213025 + 2005056 = 7695^2 + 1416^2 .

It is not a de Polignac number, because 61218081 - 2² = 61218077 is a prime.

It is a super-2 number, since 2×61218081² = 7495306882645122, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (61218083) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3745 + ... + 11681.

It is an arithmetic number, because the mean of its divisors is an integer number (7378371).

Almost surely, 2^61218081 is an apocalyptic number.

It is an amenable number.

61218081 is a deficient number, since it is larger than the sum of its proper divisors (27322371).

61218081 is a wasteful number, since it uses less digits than its factorization.

61218081 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8800 (or 8797 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 27.

The square root of 61218081 is about 7824.1984253980. The cubic root of 61218081 is about 394.1182725314.

Adding to 61218081 its reverse (18081216), we get a palindrome (79299297).

The spelling of 61218081 in words is "sixty-one million, two hundred eighteen thousand, eighty-one".