81066438 has 96 divisors (see below), whose sum is σ = 195335712. Its totient is φ = 24192000.

The previous prime is 81066409. The next prime is 81066473. The reversal of 81066438 is 83466018.

It is a happy number.

81066438 is a `hidden beast` number, since 8 + 1 + 0 + 6 + 643 + 8 = 666.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 802588 + ... + 802688.

It is an arithmetic number, because the mean of its divisors is an integer number (2034747).

Almost surely, 2^81066438 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81066438, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (97667856).

81066438 is an abundant number, since it is smaller than the sum of its proper divisors (114269274).

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

81066438 is a wasteful number, since it uses less digits than its factorization.

81066438 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 230 (or 227 counting only the distinct ones).

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

The square root of 81066438 is about 9003.6902434502. The cubic root of 81066438 is about 432.7931352786.

The spelling of 81066438 in words is "eighty-one million, sixty-six thousand, four hundred thirty-eight".