81504784 has 45 divisors (see below), whose sum is σ = 165003111. Its totient is φ = 39000960.

The previous prime is 81504781. The next prime is 81504791. The reversal of 81504784 is 48740518.

The square root of 81504784 is 9028.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 4 ways, for example, as 1795600 + 79709184 = 1340^2 + 8928^2 .

It is a Harshad number since it is a multiple of its sum of digits (37).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81504781) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 1336114 + ... + 1336174.

Almost surely, 2^81504784 is an apocalyptic number.

81504784 is the 9028-th square number.

It is an amenable number.

81504784 is an abundant number, since it is smaller than the sum of its proper divisors (83498327).

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

81504784 is an equidigital number, since it uses as much as digits as its factorization.

81504784 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 204 (or 100 counting only the distinct ones).

The product of its (nonzero) digits is 35840, while the sum is 37.

The cubic root of 81504784 is about 433.5718061487.

The spelling of 81504784 in words is "eighty-one million, five hundred four thousand, seven hundred eighty-four".