81499218 has 16 divisors (see below), whose sum is σ = 163090560. Its totient is φ = 27151056.

The previous prime is 81499163. The next prime is 81499219. The reversal of 81499218 is 81299418.

It is a super-2 number, since 2×81499218² = 13284245069223048, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 81499218.

It is not an unprimeable number, because it can be changed into a prime (81499219) 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, 14148 + ... + 19056.

It is an arithmetic number, because the mean of its divisors is an integer number (10193160).

Almost surely, 2^81499218 is an apocalyptic number.

81499218 is an abundant number, since it is smaller than the sum of its proper divisors (81591342).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81499218 is a wasteful number, since it uses less digits than its factorization.

81499218 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7681.

The product of its digits is 41472, while the sum is 42.

The square root of 81499218 is about 9027.6917315557. The cubic root of 81499218 is about 433.5619363166.

The spelling of 81499218 in words is "eighty-one million, four hundred ninety-nine thousand, two hundred eighteen".