81764928 has 126 divisors (see below), whose sum is σ = 272722086. Its totient is φ = 23353344.

The previous prime is 81764911. The next prime is 81764941. The reversal of 81764928 is 82946718.

It can be written as a sum of positive squares in only one way, i.e., 54641664 + 27123264 = 7392^2 + 5208^2 .

It is a tau number, because it is divible by the number of its divisors (126).

It is a nude number because it is divisible by every one of its digits.

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, 26776 + ... + 29672.

It is an arithmetic number, because the mean of its divisors is an integer number (2164461).

Almost surely, 2^81764928 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 81764928, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (136361043).

81764928 is an abundant number, since it is smaller than the sum of its proper divisors (190957158).

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

81764928 is a wasteful number, since it uses less digits than its factorization.

81764928 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2929 (or 2909 counting only the distinct ones).

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

The square root of 81764928 is about 9042.3961426162. The cubic root of 81764928 is about 434.0326024762.

The spelling of 81764928 in words is "eighty-one million, seven hundred sixty-four thousand, nine hundred twenty-eight".