66670456721 has 8 divisors (see below), whose sum is σ = 72737724384. Its totient is φ = 60604241920.

The previous prime is 66670456717. The next prime is 66670456729. The reversal of 66670456721 is 12765407666.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 66670456721 - 2² = 66670456717 is a prime.

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 66670456721.

It is not an unprimeable number, because it can be changed into a prime (66670456729) 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, 127775 + ... + 386868.

It is an arithmetic number, because the mean of its divisors is an integer number (9092215548).

Almost surely, 2^66670456721 is an apocalyptic number.

It is an amenable number.

66670456721 is a deficient number, since it is larger than the sum of its proper divisors (6067267663).

66670456721 is a wasteful number, since it uses less digits than its factorization.

66670456721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 526431.

The product of its (nonzero) digits is 2540160, while the sum is 50.

It can be divided in two parts, 6667045 and 6721, that added together give a palindrome (6673766).

The spelling of 66670456721 in words is "sixty-six billion, six hundred seventy million, four hundred fifty-six thousand, seven hundred twenty-one".