6621408 has 72 divisors (see below), whose sum is σ = 19125288. Its totient is φ = 2172672.

The previous prime is 6621379. The next prime is 6621413. The reversal of 6621408 is 8041266.

It is a tau number, because it is divible by the number of its divisors (72).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 23766 + ... + 24042.

It is an arithmetic number, because the mean of its divisors is an integer number (265629).

Almost surely, 2^6621408 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 6621408, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (9562644).

6621408 is an abundant number, since it is smaller than the sum of its proper divisors (12503880).

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

6621408 is a wasteful number, since it uses less digits than its factorization.

6621408 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 376 (or 365 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 27.

The square root of 6621408 is about 2573.2096688766. The cubic root of 6621408 is about 187.7803379811.

The spelling of 6621408 in words is "six million, six hundred twenty-one thousand, four hundred eight".