66381063681 has 16 divisors (see below), whose sum is σ = 90624047360. Its totient is φ = 43197371280.

The previous prime is 66381063589. The next prime is 66381063703. The reversal of 66381063681 is 18636018366.

66381063681 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 66381063681 - 2⁹ = 66381063169 is a prime.

It is a super-2 number, since 2×66381063681² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 66381063681.

It is not an unprimeable number, because it can be changed into a prime (66381053681) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 40746 + ... + 366636.

It is an arithmetic number, because the mean of its divisors is an integer number (5664002960).

Almost surely, 2^66381063681 is an apocalyptic number.

It is an amenable number.

66381063681 is a deficient number, since it is larger than the sum of its proper divisors (24242983679).

66381063681 is a wasteful number, since it uses less digits than its factorization.

66381063681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 327516.

The product of its (nonzero) digits is 746496, while the sum is 48.

The spelling of 66381063681 in words is "sixty-six billion, three hundred eighty-one million, sixty-three thousand, six hundred eighty-one".