81730945 has 8 divisors (see below), whose sum is σ = 98247744. Its totient is φ = 65271024.

The previous prime is 81730931. The next prime is 81730963. The reversal of 81730945 is 54903718.

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

It is a cyclic number.

It is not a de Polignac number, because 81730945 - 2⁹ = 81730433 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10989 + ... + 16858.

It is an arithmetic number, because the mean of its divisors is an integer number (12280968).

Almost surely, 2^81730945 is an apocalyptic number.

It is an amenable number.

81730945 is a deficient number, since it is larger than the sum of its proper divisors (16516799).

81730945 is a wasteful number, since it uses less digits than its factorization.

81730945 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28439.

The product of its (nonzero) digits is 30240, while the sum is 37.

The square root of 81730945 is about 9040.5168546937. The cubic root of 81730945 is about 433.9724635137.

The spelling of 81730945 in words is "eighty-one million, seven hundred thirty thousand, nine hundred forty-five".