6909440 has 40 divisors (see below), whose sum is σ = 16572600. Its totient is φ = 2762752.

The previous prime is 6909439. The next prime is 6909449. The reversal of 6909440 is 449096.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (40).

It is a super-2 number, since 2×6909440² = 95480722227200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (32).

It is a junction number, because it is equal to n+sod(n) for n = 6909397 and 6909406.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6909449) 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, 1211 + ... + 3909.

It is an arithmetic number, because the mean of its divisors is an integer number (414315).

Almost surely, 2^6909440 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 6909440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (8286300).

6909440 is an abundant number, since it is smaller than the sum of its proper divisors (9663160).

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

6909440 is an equidigital number, since it uses as much as digits as its factorization.

6909440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2722 (or 2706 counting only the distinct ones).

The product of its (nonzero) digits is 7776, while the sum is 32.

The square root of 6909440 is about 2628.5813664408. The cubic root of 6909440 is about 190.4646062796.

The spelling of 6909440 in words is "six million, nine hundred nine thousand, four hundred forty".