81618241 has 8 divisors (see below), whose sum is σ = 86577120. Its totient is φ = 76676928.

The previous prime is 81618239. The next prime is 81618253. The reversal of 81618241 is 14281618.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 81618241 - 2¹ = 81618239 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81618211) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5890 + ... + 14068.

It is an arithmetic number, because the mean of its divisors is an integer number (10822140).

Almost surely, 2^81618241 is an apocalyptic number.

It is an amenable number.

81618241 is a deficient number, since it is larger than the sum of its proper divisors (4958879).

81618241 is a wasteful number, since it uses less digits than its factorization.

81618241 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8783.

The product of its digits is 3072, while the sum is 31.

The square root of 81618241 is about 9034.2814324107. The cubic root of 81618241 is about 433.7728943392.

Adding to 81618241 its reverse (14281618), we get a palindrome (95899859).

The spelling of 81618241 in words is "eighty-one million, six hundred eighteen thousand, two hundred forty-one".