81738816 has 84 divisors (see below), whose sum is σ = 223973136. Its totient is φ = 26307840.

The previous prime is 81738799. The next prime is 81738823. The reversal of 81738816 is 61883718.

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 in 11 ways as a sum of consecutive naturals, for example, 184291 + ... + 184733.

Almost surely, 2^81738816 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81738816, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (111986568).

81738816 is an abundant number, since it is smaller than the sum of its proper divisors (142234320).

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

81738816 is a wasteful number, since it uses less digits than its factorization.

81738816 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 520 (or 479 counting only the distinct ones).

The product of its digits is 64512, while the sum is 42.

The square root of 81738816 is about 9040.9521622449. The cubic root of 81738816 is about 433.9863941313.

The spelling of 81738816 in words is "eighty-one million, seven hundred thirty-eight thousand, eight hundred sixteen".