81818373 has 16 divisors (see below), whose sum is σ = 134266496. Its totient is φ = 43156800.

The previous prime is 81818371. The next prime is 81818377. The reversal of 81818373 is 37381818.

It is not a de Polignac number, because 81818373 - 2¹ = 81818371 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81818371) 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, 149578 + ... + 150123.

It is an arithmetic number, because the mean of its divisors is an integer number (8391656).

Almost surely, 2^81818373 is an apocalyptic number.

It is an amenable number.

81818373 is a deficient number, since it is larger than the sum of its proper divisors (52448123).

81818373 is a wasteful number, since it uses less digits than its factorization.

81818373 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 299724.

The product of its digits is 32256, while the sum is 39.

The square root of 81818373 is about 9045.3509052994. The cubic root of 81818373 is about 434.1271492079.

It can be divided in two parts, 818 and 18373, that added together give a palindrome (19191).

The spelling of 81818373 in words is "eighty-one million, eight hundred eighteen thousand, three hundred seventy-three".