81299218 has 32 divisors (see below), whose sum is σ = 163739520. Its totient is φ = 29237760.

The previous prime is 81299213. The next prime is 81299311.

81299218 is nontrivially palindromic in base 10.

It is not an unprimeable number, because it can be changed into a prime (81299213) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 18303 + ... + 22306.

It is an arithmetic number, because the mean of its divisors is an integer number (5116860).

Almost surely, 2^81299218 is an apocalyptic number.

81299218 is an abundant number, since it is smaller than the sum of its proper divisors (82440302).

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

81299218 is a wasteful number, since it uses less digits than its factorization.

81299218 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40642.

The product of its digits is 20736, while the sum is 40.

The square root of 81299218 is about 9016.6078987610. The cubic root of 81299218 is about 433.2069905175.

The spelling of 81299218 in words is "eighty-one million, two hundred ninety-nine thousand, two hundred eighteen".