81866304 has 189 divisors, whose sum is σ = 263157843. Its totient is φ = 24321024.

The previous prime is 81866297. The next prime is 81866321. The reversal of 81866304 is 40366818.

It is a happy number.

The square root of 81866304 is 9048.

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

81866304 is a `hidden beast` number, since 8 + 18 + 6 + 630 + 4 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 10497600 + 71368704 = 3240^2 + 8448^2 .

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 2822962 + ... + 2822990.

Almost surely, 2^81866304 is an apocalyptic number.

81866304 is the 9048-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81866304

81866304 is an abundant number, since it is smaller than the sum of its proper divisors (181291539).

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

81866304 is a wasteful number, since it uses less digits than its factorization.

81866304 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 102 (or 47 counting only the distinct ones).

The product of its (nonzero) digits is 27648, while the sum is 36.

The cubic root of 81866304 is about 434.2119063990.

Multiplying 81866304 by its sum of digits (36), we get a square (2947186944 = 54288²).

81866304 divided by its sum of digits (36) gives a square (2274064 = 1508²).

The spelling of 81866304 in words is "eighty-one million, eight hundred sixty-six thousand, three hundred four".