81818416 has 40 divisors (see below), whose sum is σ = 168699024. Its totient is φ = 38307840.

The previous prime is 81818377. The next prime is 81818419. The reversal of 81818416 is 61481818.

81818416 = T₇₃₈₄ + T₇₃₈₅ + T₇₃₈₆.

It is a Smith number, since the sum of its digits (37) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (81818419) 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 7 ways as a sum of consecutive naturals, for example, 62731 + ... + 64021.

Almost surely, 2^81818416 is an apocalyptic number.

81818416 is the 7386-th centered triangular number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81818416, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (84349512).

81818416 is an abundant number, since it is smaller than the sum of its proper divisors (86880608).

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

81818416 is a wasteful number, since it uses less digits than its factorization.

81818416 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1549 (or 1543 counting only the distinct ones).

The product of its digits is 12288, while the sum is 37.

The square root of 81818416 is about 9045.3532822107. The cubic root of 81818416 is about 434.1272252604.

The spelling of 81818416 in words is "eighty-one million, eight hundred eighteen thousand, four hundred sixteen".