6721605 has 48 divisors (see below), whose sum is σ = 13089024. Its totient is φ = 3162240.

The previous prime is 6721577. The next prime is 6721609. The reversal of 6721605 is 5061276.

It is not a de Polignac number, because 6721605 - 2⁶ = 6721541 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6721609) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 18132 + ... + 18498.

It is an arithmetic number, because the mean of its divisors is an integer number (272688).

Almost surely, 2^6721605 is an apocalyptic number.

It is an amenable number.

6721605 is a deficient number, since it is larger than the sum of its proper divisors (6367419).

6721605 is a wasteful number, since it uses less digits than its factorization.

6721605 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 426 (or 423 counting only the distinct ones).

The product of its (nonzero) digits is 2520, while the sum is 27.

The square root of 6721605 is about 2592.6058319768. The cubic root of 6721605 is about 188.7227816256.

The spelling of 6721605 in words is "six million, seven hundred twenty-one thousand, six hundred five".