6440388 has 12 divisors (see below), whose sum is σ = 15027600. Its totient is φ = 2146792.

The previous prime is 6440383. The next prime is 6440389. The reversal of 6440388 is 8830446.

It is a tau number, because it is divible by the number of its divisors (12).

It is not an unprimeable number, because it can be changed into a prime (6440383) 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, 268338 + ... + 268361.

It is an arithmetic number, because the mean of its divisors is an integer number (1252300).

Almost surely, 2^6440388 is an apocalyptic number.

It is an amenable number.

6440388 is an abundant number, since it is smaller than the sum of its proper divisors (8587212).

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

6440388 is a wasteful number, since it uses less digits than its factorization.

6440388 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 536706 (or 536704 counting only the distinct ones).

The product of its (nonzero) digits is 18432, while the sum is 33.

The square root of 6440388 is about 2537.7919536479. The cubic root of 6440388 is about 186.0532856928.

The spelling of 6440388 in words is "six million, four hundred forty thousand, three hundred eighty-eight".