6621440 has 72 divisors (see below), whose sum is σ = 18150720. Its totient is φ = 2267136.

The previous prime is 6621421. The next prime is 6621451. The reversal of 6621440 is 441266.

It is a happy number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8591 + ... + 9329.

Almost surely, 2^6621440 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 6621440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (9075360).

6621440 is an abundant number, since it is smaller than the sum of its proper divisors (11529280).

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

6621440 is an equidigital number, since it uses as much as digits as its factorization.

6621440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 767 (or 753 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 23.

The square root of 6621440 is about 2573.2158867845. The cubic root of 6621440 is about 187.7806404827.

The spelling of 6621440 in words is "six million, six hundred twenty-one thousand, four hundred forty".