4001721 has 16 divisors (see below), whose sum is σ = 5522688. Its totient is φ = 2576000.

The previous prime is 4001719. The next prime is 4001741. The reversal of 4001721 is 1271004.

It is a cyclic number.

It is not a de Polignac number, because 4001721 - 2¹ = 4001719 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 4001721.

It is not an unprimeable number, because it can be changed into a prime (4001741) 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, 14101 + ... + 14381.

It is an arithmetic number, because the mean of its divisors is an integer number (345168).

Almost surely, 2^4001721 is an apocalyptic number.

It is an amenable number.

4001721 is a deficient number, since it is larger than the sum of its proper divisors (1520967).

4001721 is a wasteful number, since it uses less digits than its factorization.

4001721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 432.

The product of its (nonzero) digits is 56, while the sum is 15.

The square root of 4001721 is about 2000.4302037312. The cubic root of 4001721 is about 158.7628679093.

Adding to 4001721 its reverse (1271004), we get a palindrome (5272725).

The spelling of 4001721 in words is "four million, one thousand, seven hundred twenty-one".