6644443861 has 4 divisors (see below), whose sum is σ = 7248484224. Its totient is φ = 6040403500.

The previous prime is 6644443859. The next prime is 6644443889. The reversal of 6644443861 is 1683444466.

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.

It is a cyclic number.

It is not a de Polignac number, because 6644443861 - 2¹ = 6644443859 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6644443891) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 302020165 + ... + 302020186.

It is an arithmetic number, because the mean of its divisors is an integer number (1812121056).

Almost surely, 2^6644443861 is an apocalyptic number.

It is an amenable number.

6644443861 is a deficient number, since it is larger than the sum of its proper divisors (604040363).

6644443861 is a wasteful number, since it uses less digits than its factorization.

6644443861 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 604040362.

The product of its digits is 1327104, while the sum is 46.

The square root of 6644443861 is about 81513.4581587605. The cubic root of 6644443861 is about 1879.9784837020.

The spelling of 6644443861 in words is "six billion, six hundred forty-four million, four hundred forty-three thousand, eight hundred sixty-one".