81344818 has 4 divisors (see below), whose sum is σ = 122017230. Its totient is φ = 40672408.

The previous prime is 81344807. The next prime is 81344831. The reversal of 81344818 is 81844318.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 78730129 + 2614689 = 8873^2 + 1617^2 .

It is an unprimeable number.

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 as a sum of consecutive naturals, namely, 20336203 + ... + 20336206.

Almost surely, 2^81344818 is an apocalyptic number.

81344818 is a deficient number, since it is larger than the sum of its proper divisors (40672412).

81344818 is a wasteful number, since it uses less digits than its factorization.

81344818 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40672411.

The product of its digits is 24576, while the sum is 37.

The square root of 81344818 is about 9019.1362114118. The cubic root of 81344818 is about 433.2879693472.

Subtracting 81344818 from its reverse (81844318), we obtain a triangular number (499500 = T₉₉₉).

The spelling of 81344818 in words is "eighty-one million, three hundred forty-four thousand, eight hundred eighteen".