81718006 has 4 divisors (see below), whose sum is σ = 122577012. Its totient is φ = 40859002.

The previous prime is 81718003. The next prime is 81718019. The reversal of 81718006 is 60081718.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 60081718 = 2 ⋅30040859.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81718003) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20429500 + ... + 20429503.

It is an arithmetic number, because the mean of its divisors is an integer number (30644253).

Almost surely, 2^81718006 is an apocalyptic number.

81718006 is a deficient number, since it is larger than the sum of its proper divisors (40859006).

81718006 is a wasteful number, since it uses less digits than its factorization.

81718006 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40859005.

The product of its (nonzero) digits is 2688, while the sum is 31.

The square root of 81718006 is about 9039.8012146286. The cubic root of 81718006 is about 433.9495612701.

The spelling of 81718006 in words is "eighty-one million, seven hundred eighteen thousand, six".