81926784 has 144 divisors (see below), whose sum is σ = 250076970. Its totient is φ = 25740288.

The previous prime is 81926777. The next prime is 81926807. The reversal of 81926784 is 48762918.

It can be written as a sum of positive squares in only one way, i.e., 46785600 + 35141184 = 6840^2 + 5928^2 .

It is a tau number, because it is divible by the number of its divisors (144).

It is an unprimeable number.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 415774 + ... + 415970.

Almost surely, 2^81926784 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 81926784, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (125038485).

81926784 is an abundant number, since it is smaller than the sum of its proper divisors (168150186).

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

81926784 is a wasteful number, since it uses less digits than its factorization.

81926784 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 255 (or 221 counting only the distinct ones).

The product of its digits is 193536, while the sum is 45.

The square root of 81926784 is about 9051.3415580233. The cubic root of 81926784 is about 434.3188070021.

The spelling of 81926784 in words is "eighty-one million, nine hundred twenty-six thousand, seven hundred eighty-four".