2321721 has 12 divisors (see below), whose sum is σ = 3409380. Its totient is φ = 1522080.

The previous prime is 2321701. The next prime is 2321747. The reversal of 2321721 is 1271232.

It can be written as a sum of positive squares in 2 ways, for example, as 1299600 + 1022121 = 1140^2 + 1011^2 .

It is not a de Polignac number, because 2321721 - 2¹⁰ = 2320697 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 2321694 and 2321703.

It is not an unprimeable number, because it can be changed into a prime (2321701) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1566 + ... + 2663.

It is an arithmetic number, because the mean of its divisors is an integer number (284115).

2^2321721 is an apocalyptic number.

It is an amenable number.

2321721 is a deficient number, since it is larger than the sum of its proper divisors (1087659).

2321721 is a wasteful number, since it uses less digits than its factorization.

2321721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4296 (or 4293 counting only the distinct ones).

The product of its digits is 168, while the sum is 18.

The square root of 2321721 is about 1523.7194623683. The cubic root of 2321721 is about 132.4148450115.

Adding to 2321721 its reverse (1271232), we get a palindrome (3592953).

It can be divided in two parts, 232 and 1721, that added together give a triangular number (1953 = T₆₂).

The spelling of 2321721 in words is "two million, three hundred twenty-one thousand, seven hundred twenty-one".