6731721 has 16 divisors (see below), whose sum is σ = 10019520. Its totient is φ = 4466880.

The previous prime is 6731717. The next prime is 6731729. The reversal of 6731721 is 1271376.

It is not a de Polignac number, because 6731721 - 2² = 6731717 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

6731721 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6731729) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 7201 + ... + 8081.

It is an arithmetic number, because the mean of its divisors is an integer number (626220).

Almost surely, 2^6731721 is an apocalyptic number.

It is an amenable number.

6731721 is a deficient number, since it is larger than the sum of its proper divisors (3287799).

6731721 is a wasteful number, since it uses less digits than its factorization.

6731721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1173 (or 1167 counting only the distinct ones).

The product of its digits is 1764, while the sum is 27.

The square root of 6731721 is about 2594.5560313857. The cubic root of 6731721 is about 188.8174099531.

The spelling of 6731721 in words is "six million, seven hundred thirty-one thousand, seven hundred twenty-one".