81815073 has 8 divisors (see below), whose sum is σ = 110088000. Its totient is φ = 54042768.

The previous prime is 81815057. The next prime is 81815099. The reversal of 81815073 is 37051818.

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

It is not a de Polignac number, because 81815073 - 2⁴ = 81815057 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81811073) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 124773 + ... + 125426.

It is an arithmetic number, because the mean of its divisors is an integer number (13761000).

Almost surely, 2^81815073 is an apocalyptic number.

It is an amenable number.

81815073 is a deficient number, since it is larger than the sum of its proper divisors (28272927).

81815073 is a wasteful number, since it uses less digits than its factorization.

81815073 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 250311.

The product of its (nonzero) digits is 6720, while the sum is 33.

The square root of 81815073 is about 9045.1684893096. The cubic root of 81815073 is about 434.1213125447.

The spelling of 81815073 in words is "eighty-one million, eight hundred fifteen thousand, seventy-three".