81522518 has 32 divisors (see below), whose sum is σ = 154752768. Its totient is φ = 31284000.

The previous prime is 81522499. The next prime is 81522523.

It is a happy number.

81522518 is nontrivially palindromic in base 10.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6368 + ... + 14268.

It is an arithmetic number, because the mean of its divisors is an integer number (4836024).

Almost surely, 2^81522518 is an apocalyptic number.

81522518 is a deficient number, since it is larger than the sum of its proper divisors (73230250).

81522518 is a wasteful number, since it uses less digits than its factorization.

81522518 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7988.

The product of its digits is 6400, while the sum is 32.

The square root of 81522518 is about 9028.9821131731. The cubic root of 81522518 is about 433.6032497215.

The spelling of 81522518 in words is "eighty-one million, five hundred twenty-two thousand, five hundred eighteen".