81716018 has 4 divisors (see below), whose sum is σ = 122574030. Its totient is φ = 40858008.

The previous prime is 81716009. The next prime is 81716053. The reversal of 81716018 is 81061718.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 73496329 + 8219689 = 8573^2 + 2867^2 .

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20429003 + ... + 20429006.

Almost surely, 2^81716018 is an apocalyptic number.

81716018 is a deficient number, since it is larger than the sum of its proper divisors (40858012).

81716018 is a wasteful number, since it uses less digits than its factorization.

81716018 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40858011.

The product of its (nonzero) digits is 2688, while the sum is 32.

The square root of 81716018 is about 9039.6912557897. The cubic root of 81716018 is about 433.9460422630.

The spelling of 81716018 in words is "eighty-one million, seven hundred sixteen thousand, eighteen".