6721408 has 16 divisors (see below), whose sum is σ = 13390560. Its totient is φ = 3360640.

The previous prime is 6721387. The next prime is 6721411. The reversal of 6721408 is 8041276.

It is a tau number, because it is divible by the number of its divisors (16).

It is a Smith number, since the sum of its digits (28) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 26128 + ... + 26383.

It is an arithmetic number, because the mean of its divisors is an integer number (836910).

Almost surely, 2^6721408 is an apocalyptic number.

It is an amenable number.

6721408 is a deficient number, since it is larger than the sum of its proper divisors (6669152).

6721408 is an equidigital number, since it uses as much as digits as its factorization.

6721408 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 52525 (or 52513 counting only the distinct ones).

The product of its (nonzero) digits is 2688, while the sum is 28.

The square root of 6721408 is about 2592.5678390353. The cubic root of 6721408 is about 188.7209378818.

It can be divided in two parts, 672 and 1408, that added together give a triangular number (2080 = T₆₄).

The spelling of 6721408 in words is "six million, seven hundred twenty-one thousand, four hundred eight".