6721081 has 4 divisors (see below), whose sum is σ = 6736500. Its totient is φ = 6705664.

The previous prime is 6721061. The next prime is 6721093. The reversal of 6721081 is 1801276.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 1357225 + 5363856 = 1165^2 + 2316^2 .

It is a cyclic number.

It is not a de Polignac number, because 6721081 - 2¹⁵ = 6688313 is a prime.

It is a super-2 number, since 2×6721081² = 90345859617122, which contains 22 as substring.

It is a Duffinian number.

6721081 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (6721051) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7036 + ... + 7933.

It is an arithmetic number, because the mean of its divisors is an integer number (1684125).

Almost surely, 2^6721081 is an apocalyptic number.

It is an amenable number.

6721081 is a deficient number, since it is larger than the sum of its proper divisors (15419).

6721081 is a wasteful number, since it uses less digits than its factorization.

6721081 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15418.

The product of its (nonzero) digits is 672, while the sum is 25.

The square root of 6721081 is about 2592.5047733804. The cubic root of 6721081 is about 188.7178773749.

The spelling of 6721081 in words is "six million, seven hundred twenty-one thousand, eighty-one".