6644974221665 has 8 divisors (see below), whose sum is σ = 8587351301928. Its totient is φ = 4907057886720.

The previous prime is 6644974221607. The next prime is 6644974221701. The reversal of 6644974221665 is 5661224794466.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 106459290961 + 6538514930704 = 326281^2 + 2557052^2 .

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

It is not a de Polignac number, because 6644974221665 - 2⁶ = 6644974221601 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 6644974221598 and 6644974221607.

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, 51115186256 + ... + 51115186385.

It is an arithmetic number, because the mean of its divisors is an integer number (1073418912741).

Almost surely, 2^{6644974221665} is an apocalyptic number.

6644974221665 is a gapful number since it is divisible by the number (65) formed by its first and last digit.

It is an amenable number.

6644974221665 is a deficient number, since it is larger than the sum of its proper divisors (1942377080263).

6644974221665 is a wasteful number, since it uses less digits than its factorization.

6644974221665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 102230372659.

The product of its digits is 104509440, while the sum is 62.

The spelling of 6644974221665 in words is "six trillion, six hundred forty-four billion, nine hundred seventy-four million, two hundred twenty-one thousand, six hundred sixty-five".