81717044851 has 8 divisors (see below), whose sum is σ = 88636088240. Its totient is φ = 74888446752.

The previous prime is 81717044833. The next prime is 81717044869. The reversal of 81717044851 is 15844071718.

It is an interprime number because it is at equal distance from previous prime (81717044833) and next prime (81717044869).

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81717044851 is a prime.

It is a super-2 number, since 2×81717044851² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81717044891) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 22609440 + ... + 22613053.

It is an arithmetic number, because the mean of its divisors is an integer number (11079511030).

Almost surely, 2^81717044851 is an apocalyptic number.

81717044851 is a deficient number, since it is larger than the sum of its proper divisors (6919043389).

81717044851 is a wasteful number, since it uses less digits than its factorization.

81717044851 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 45222645.

The product of its (nonzero) digits is 250880, while the sum is 46.

The spelling of 81717044851 in words is "eighty-one billion, seven hundred seventeen million, forty-four thousand, eight hundred fifty-one".