4023721 has 12 divisors (see below), whose sum is σ = 4512780. Its totient is φ = 3581760.

The previous prime is 4023703. The next prime is 4023727. The reversal of 4023721 is 1273204.

It can be written as a sum of positive squares in 6 ways, for example, as 912025 + 3111696 = 955^2 + 1764^2 .

It is not a de Polignac number, because 4023721 - 2¹⁷ = 3892649 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (4023727) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 4491 + ... + 5311.

It is an arithmetic number, because the mean of its divisors is an integer number (376065).

Almost surely, 2^4023721 is an apocalyptic number.

It is an amenable number.

4023721 is a deficient number, since it is larger than the sum of its proper divisors (489059).

4023721 is a wasteful number, since it uses less digits than its factorization.

4023721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 876 (or 863 counting only the distinct ones).

The product of its (nonzero) digits is 336, while the sum is 19.

The square root of 4023721 is about 2005.9214840068. The cubic root of 4023721 is about 159.0532764519.

Adding to 4023721 its reverse (1273204), we get a palindrome (5296925).

The spelling of 4023721 in words is "four million, twenty-three thousand, seven hundred twenty-one".