81171768013 has 8 divisors (see below), whose sum is σ = 93016444928. Its totient is φ = 69389268624.

The previous prime is 81171767921. The next prime is 81171768017. The reversal of 81171768013 is 31086717118.

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 81171768013 - 2¹³ = 81171759821 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81171768017) 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, 15541581 + ... + 15546802.

It is an arithmetic number, because the mean of its divisors is an integer number (11627055616).

Almost surely, 2^81171768013 is an apocalyptic number.

It is an amenable number.

81171768013 is a deficient number, since it is larger than the sum of its proper divisors (11844676915).

81171768013 is a wasteful number, since it uses less digits than its factorization.

81171768013 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31088763.

The product of its (nonzero) digits is 56448, while the sum is 43.

The spelling of 81171768013 in words is "eighty-one billion, one hundred seventy-one million, seven hundred sixty-eight thousand, thirteen".