81166506 has 16 divisors (see below), whose sum is σ = 162502848. Its totient is φ = 27027200.

The previous prime is 81166489. The next prime is 81166507. The reversal of 81166506 is 60566118.

It is not an unprimeable number, because it can be changed into a prime (81166507) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 375 + ... + 12746.

It is an arithmetic number, because the mean of its divisors is an integer number (10156428).

Almost surely, 2^81166506 is an apocalyptic number.

81166506 is an abundant number, since it is smaller than the sum of its proper divisors (81336342).

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

81166506 is a wasteful number, since it uses less digits than its factorization.

81166506 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14157.

The product of its (nonzero) digits is 8640, while the sum is 33.

The square root of 81166506 is about 9009.2455843983. The cubic root of 81166506 is about 432.9711412726.

The spelling of 81166506 in words is "eighty-one million, one hundred sixty-six thousand, five hundred six".