6721281 has 18 divisors (see below), whose sum is σ = 11294322. Its totient is φ = 3840480.

The previous prime is 6721277. The next prime is 6721283. The reversal of 6721281 is 1821276.

It can be written as a sum of positive squares in only one way, i.e., 6350400 + 370881 = 2520^2 + 609^2 .

It is not a de Polignac number, because 6721281 - 2² = 6721277 is a prime.

It is a super-2 number, since 2×6721281² = 90351236561922, which contains 22 as substring.

6721281 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (6721283) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 7180 + ... + 8061.

Almost surely, 2^6721281 is an apocalyptic number.

It is an amenable number.

6721281 is a deficient number, since it is larger than the sum of its proper divisors (4573041).

6721281 is a wasteful number, since it uses less digits than its factorization.

6721281 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15261 (or 15251 counting only the distinct ones).

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

The square root of 6721281 is about 2592.5433458286. The cubic root of 6721281 is about 188.7197492564.

It can be divided in two parts, 672 and 1281, that added together give a triangular number (1953 = T₆₂).

The spelling of 6721281 in words is "six million, seven hundred twenty-one thousand, two hundred eighty-one".