6644778888845 has 8 divisors (see below), whose sum is σ = 8031937110264. Its totient is φ = 5277021481984.

The previous prime is 6644778888779. The next prime is 6644778888973. The reversal of 6644778888845 is 5488888774466.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 1072521211876 + 5572257676969 = 1035626^2 + 2360563^2 .

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 6644778888845 - 2¹⁴ = 6644778872461 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4850202884 + ... + 4850204253.

It is an arithmetic number, because the mean of its divisors is an integer number (1003992138783).

Almost surely, 2^{6644778888845} is an apocalyptic number.

It is an amenable number.

6644778888845 is a deficient number, since it is larger than the sum of its proper divisors (1387158221419).

6644778888845 is a wasteful number, since it uses less digits than its factorization.

6644778888845 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9700407279.

The product of its digits is 18496880640, while the sum is 83.

The spelling of 6644778888845 in words is "six trillion, six hundred forty-four billion, seven hundred seventy-eight million, eight hundred eighty-eight thousand, eight hundred forty-five".