66621680641 has 8 divisors (see below), whose sum is σ = 66706738560. Its totient is φ = 66536658048.

The previous prime is 66621680569. The next prime is 66621680651. The reversal of 66621680641 is 14608612666.

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 66621680641 - 2⁹ = 66621680129 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 66621680591 and 66621680600.

It is not an unprimeable number, because it can be changed into a prime (66621680651) 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, 7206300 + ... + 7215538.

It is an arithmetic number, because the mean of its divisors is an integer number (8338342320).

Almost surely, 2^66621680641 is an apocalyptic number.

It is an amenable number.

66621680641 is a deficient number, since it is larger than the sum of its proper divisors (85057919).

66621680641 is an equidigital number, since it uses as much as digits as its factorization.

66621680641 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17663.

The product of its (nonzero) digits is 497664, while the sum is 46.

The spelling of 66621680641 in words is "sixty-six billion, six hundred twenty-one million, six hundred eighty thousand, six hundred forty-one".