66713518081 has 24 divisors (see below), whose sum is σ = 82674833760. Its totient is φ = 53489020032.

The previous prime is 66713518037. The next prime is 66713518093. The reversal of 66713518081 is 18081531766.

It is not a de Polignac number, because 66713518081 - 2⁹ = 66713517569 is a prime.

It is a super-2 number, since 2×66713518081² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66713518021) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 109891 + ... + 381448.

It is an arithmetic number, because the mean of its divisors is an integer number (3444784740).

Almost surely, 2^66713518081 is an apocalyptic number.

It is an amenable number.

66713518081 is a deficient number, since it is larger than the sum of its proper divisors (15961315679).

66713518081 is a wasteful number, since it uses less digits than its factorization.

66713518081 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 491533 (or 491526 counting only the distinct ones).

The product of its (nonzero) digits is 241920, while the sum is 46.

The spelling of 66713518081 in words is "sixty-six billion, seven hundred thirteen million, five hundred eighteen thousand, eighty-one".