6721128 has 48 divisors (see below), whose sum is σ = 18322980. Its totient is φ = 2225664.

The previous prime is 6721123. The next prime is 6721133. The reversal of 6721128 is 8211276.

It is an interprime number because it is at equal distance from previous prime (6721123) and next prime (6721133).

It can be written as a sum of positive squares in 2 ways, for example, as 6140484 + 580644 = 2478^2 + 762^2 .

It is not an unprimeable number, because it can be changed into a prime (6721123) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 19776 + ... + 20112.

Almost surely, 2^6721128 is an apocalyptic number.

It is an amenable number.

6721128 is an abundant number, since it is smaller than the sum of its proper divisors (11601852).

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

6721128 is a wasteful number, since it uses less digits than its factorization.

6721128 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 626 (or 619 counting only the distinct ones).

The product of its digits is 1344, while the sum is 27.

The square root of 6721128 is about 2592.5138379573. The cubic root of 6721128 is about 188.7183172704.

The spelling of 6721128 in words is "six million, seven hundred twenty-one thousand, one hundred twenty-eight".