6440988 has 12 divisors (see below), whose sum is σ = 15029000. Its totient is φ = 2146992.

The previous prime is 6440983. The next prime is 6440999. The reversal of 6440988 is 8890446.

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

It is a super-2 number, since 2×6440988² = 82972652832288, which contains 22 as substring.

It is a hoax number, since the sum of its digits (39) coincides with the sum of the digits of its distinct prime factors.

It is an Ulam number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6440983) 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, 268363 + ... + 268386.

Almost surely, 2^6440988 is an apocalyptic number.

It is an amenable number.

6440988 is an abundant number, since it is smaller than the sum of its proper divisors (8588012).

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

6440988 is a wasteful number, since it uses less digits than its factorization.

6440988 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 536756 (or 536754 counting only the distinct ones).

The product of its (nonzero) digits is 55296, while the sum is 39.

The square root of 6440988 is about 2537.9101638947. The cubic root of 6440988 is about 186.0590632176.

The spelling of 6440988 in words is "six million, four hundred forty thousand, nine hundred eighty-eight".