6444400866 has 16 divisors (see below), whose sum is σ = 13449184704. Its totient is φ = 2054736464.

The previous prime is 6444400861. The next prime is 6444400871. The reversal of 6444400866 is 6680044446.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (6444400861) and next prime (6444400871).

It is not an unprimeable number, because it can be changed into a prime (6444400861) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 23349141 + ... + 23349416.

It is an arithmetic number, because the mean of its divisors is an integer number (840574044).

Almost surely, 2^6444400866 is an apocalyptic number.

6444400866 is an abundant number, since it is smaller than the sum of its proper divisors (7004783838).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

6444400866 is a wasteful number, since it uses less digits than its factorization.

6444400866 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 46698585.

The product of its (nonzero) digits is 442368, while the sum is 42.

The square root of 6444400866 is about 80277.0257670275. The cubic root of 6444400866 is about 1860.9191959151.

The spelling of 6444400866 in words is "six billion, four hundred forty-four million, four hundred thousand, eight hundred sixty-six".