81744666 has 8 divisors (see below), whose sum is σ = 163489344. Its totient is φ = 27248220.

The previous prime is 81744661. The next prime is 81744667. The reversal of 81744666 is 66644718.

It is a sphenic number, since it is the product of 3 distinct primes.

81744666 is an admirable number.

It is not an unprimeable number, because it can be changed into a prime (81744661) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6812050 + ... + 6812061.

It is an arithmetic number, because the mean of its divisors is an integer number (20436168).

Almost surely, 2^81744666 is an apocalyptic number.

81744666 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

81744666 is a wasteful number, since it uses less digits than its factorization.

81744666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13624116.

The product of its digits is 193536, while the sum is 42.

The square root of 81744666 is about 9041.2756843269. The cubic root of 81744666 is about 433.9967472698.

The spelling of 81744666 in words is "eighty-one million, seven hundred forty-four thousand, six hundred sixty-six".