81817611 has 16 divisors (see below), whose sum is σ = 110990880. Its totient is φ = 53602560.

The previous prime is 81817607. The next prime is 81817627. The reversal of 81817611 is 11671818.

It is not a de Polignac number, because 81817611 - 2² = 81817607 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81817661) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 47481 + ... + 49173.

It is an arithmetic number, because the mean of its divisors is an integer number (6936930).

Almost surely, 2^81817611 is an apocalyptic number.

81817611 is a deficient number, since it is larger than the sum of its proper divisors (29173269).

81817611 is a wasteful number, since it uses less digits than its factorization.

81817611 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1966.

The product of its digits is 2688, while the sum is 33.

The square root of 81817611 is about 9045.3087841157. The cubic root of 81817611 is about 434.1258014833.

It can be divided in two parts, 81817 and 611, that added together give a palindrome (82428).

The spelling of 81817611 in words is "eighty-one million, eight hundred seventeen thousand, six hundred eleven".