66440644751 has 8 divisors (see below), whose sum is σ = 71708037744. Its totient is φ = 61195619520.

The previous prime is 66440644729. The next prime is 66440644849. The reversal of 66440644751 is 15744604466.

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 66440644751 - 2¹⁸ = 66440382607 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 66440644696 and 66440644705.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66440646751) 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, 5585765 + ... + 5597646.

It is an arithmetic number, because the mean of its divisors is an integer number (8963504718).

Almost surely, 2^66440644751 is an apocalyptic number.

66440644751 is a deficient number, since it is larger than the sum of its proper divisors (5267392993).

66440644751 is a wasteful number, since it uses less digits than its factorization.

66440644751 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11183881.

The product of its (nonzero) digits is 1935360, while the sum is 47.

The spelling of 66440644751 in words is "sixty-six billion, four hundred forty million, six hundred forty-four thousand, seven hundred fifty-one".