66638046321 has 72 divisors (see below), whose sum is σ = 122398380000. Its totient is φ = 34546538880.

The previous prime is 66638046317. The next prime is 66638046347. The reversal of 66638046321 is 12364083666.

It is not a de Polignac number, because 66638046321 - 2² = 66638046317 is a prime.

It is not an unprimeable number, because it can be changed into a prime (66638046361) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 2406885 + ... + 2434413.

It is an arithmetic number, because the mean of its divisors is an integer number (1699977500).

Almost surely, 2^66638046321 is an apocalyptic number.

It is an amenable number.

66638046321 is a deficient number, since it is larger than the sum of its proper divisors (55760333679).

66638046321 is a wasteful number, since it uses less digits than its factorization.

66638046321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28059 (or 28049 counting only the distinct ones).

The product of its (nonzero) digits is 746496, while the sum is 45.

The spelling of 66638046321 in words is "sixty-six billion, six hundred thirty-eight million, forty-six thousand, three hundred twenty-one".