66740606721 has 8 divisors (see below), whose sum is σ = 98874972960. Its totient is φ = 44493737796.

The previous prime is 66740606711. The next prime is 66740606741. The reversal of 66740606721 is 12760604766.

It is a happy number.

It is not a de Polignac number, because 66740606721 - 2⁹ = 66740606209 is a prime.

It is not an unprimeable number, because it can be changed into a prime (66740606701) 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, 1235937135 + ... + 1235937188.

It is an arithmetic number, because the mean of its divisors is an integer number (12359371620).

Almost surely, 2^66740606721 is an apocalyptic number.

It is an amenable number.

66740606721 is a deficient number, since it is larger than the sum of its proper divisors (32134366239).

66740606721 is a wasteful number, since it uses less digits than its factorization.

66740606721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2471874332 (or 2471874326 counting only the distinct ones).

The product of its (nonzero) digits is 508032, while the sum is 45.

The spelling of 66740606721 in words is "sixty-six billion, seven hundred forty million, six hundred six thousand, seven hundred twenty-one".