66542244641 has 8 divisors (see below), whose sum is σ = 66778425000. Its totient is φ = 66306126592.

The previous prime is 66542244617. The next prime is 66542244647. The reversal of 66542244641 is 14644224566.

It can be written as a sum of positive squares in 4 ways, for example, as 23869014016 + 42673230625 = 154496^2 + 206575^2 .

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-66542244641 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 66542244592 and 66542244601.

It is not an unprimeable number, because it can be changed into a prime (66542244647) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3539735 + ... + 3558483.

It is an arithmetic number, because the mean of its divisors is an integer number (8347303125).

Almost surely, 2^66542244641 is an apocalyptic number.

It is an amenable number.

66542244641 is a deficient number, since it is larger than the sum of its proper divisors (236180359).

66542244641 is a wasteful number, since it uses less digits than its factorization.

66542244641 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31155.

The product of its digits is 1105920, while the sum is 44.

The spelling of 66542244641 in words is "sixty-six billion, five hundred forty-two million, two hundred forty-four thousand, six hundred forty-one".