6444536611978 has 4 divisors (see below), whose sum is σ = 9666804917970. Its totient is φ = 3222268305988.

The previous prime is 6444536611969. The next prime is 6444536612011. The reversal of 6444536611978 is 8791166354446.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 3373220776689 + 3071315835289 = 1836633^2 + 1752517^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1611134152993 + ... + 1611134152996.

Almost surely, 2^{6444536611978} is an apocalyptic number.

6444536611978 is a deficient number, since it is larger than the sum of its proper divisors (3222268305992).

6444536611978 is a wasteful number, since it uses less digits than its factorization.

6444536611978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3222268305991.

The product of its digits is 104509440, while the sum is 64.

The spelling of 6444536611978 in words is "six trillion, four hundred forty-four billion, five hundred thirty-six million, six hundred eleven thousand, nine hundred seventy-eight".