6441994187 has 4 divisors (see below), whose sum is σ = 6616102176. Its totient is φ = 6267886200.

The previous prime is 6441994157. The next prime is 6441994193. The reversal of 6441994187 is 7814991446.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 7814991446 = 2 ⋅3907495723.

It is a cyclic number.

It is not a de Polignac number, because 6441994187 - 2⁸ = 6441993931 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (6441994147) 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, 87053939 + ... + 87054012.

It is an arithmetic number, because the mean of its divisors is an integer number (1654025544).

Almost surely, 2^6441994187 is an apocalyptic number.

6441994187 is a deficient number, since it is larger than the sum of its proper divisors (174107989).

6441994187 is a wasteful number, since it uses less digits than its factorization.

6441994187 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 174107988.

The product of its digits is 1741824, while the sum is 53.

The square root of 6441994187 is about 80262.0345306547. The cubic root of 6441994187 is about 1860.6875119630.

The spelling of 6441994187 in words is "six billion, four hundred forty-one million, nine hundred ninety-four thousand, one hundred eighty-seven".