66681121007 has 4 divisors (see below), whose sum is σ = 67167844656. Its totient is φ = 66194397360.

The previous prime is 66681120953. The next prime is 66681121033. The reversal of 66681121007 is 70012118666.

66681121007 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 66681121007 - 2²⁸ = 66412685551 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 (66681121037) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 243361619 + ... + 243361892.

It is an arithmetic number, because the mean of its divisors is an integer number (16791961164).

Almost surely, 2^66681121007 is an apocalyptic number.

66681121007 is a deficient number, since it is larger than the sum of its proper divisors (486723649).

66681121007 is a wasteful number, since it uses less digits than its factorization.

66681121007 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 486723648.

The product of its (nonzero) digits is 24192, while the sum is 38.

The spelling of 66681121007 in words is "sixty-six billion, six hundred eighty-one million, one hundred twenty-one thousand, seven".