6643260636401 has 4 divisors (see below), whose sum is σ = 6643266972672. Its totient is φ = 6643254300132.

The previous prime is 6643260636263. The next prime is 6643260636443. The reversal of 6643260636401 is 1046360623466.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-6643260636401 is a prime.

It is a Duffinian number.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 1179281 + ... + 3831086.

It is an arithmetic number, because the mean of its divisors is an integer number (1660816743168).

Almost surely, 2^{6643260636401} is an apocalyptic number.

It is an amenable number.

6643260636401 is a deficient number, since it is larger than the sum of its proper divisors (6336271).

6643260636401 is a wasteful number, since it uses less digits than its factorization.

6643260636401 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6336270.

The product of its (nonzero) digits is 2239488, while the sum is 47.

The spelling of 6643260636401 in words is "six trillion, six hundred forty-three billion, two hundred sixty million, six hundred thirty-six thousand, four hundred one".