4391721 has 12 divisors (see below), whose sum is σ = 6378372. Its totient is φ = 2911776.

The previous prime is 4391713. The next prime is 4391741. The reversal of 4391721 is 1271934.

It can be written as a sum of positive squares in 2 ways, for example, as 3515625 + 876096 = 1875^2 + 936^2 .

It is not a de Polignac number, because 4391721 - 2³ = 4391713 is a prime.

It is not an unprimeable number, because it can be changed into a prime (4391711) 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, 535 + ... + 3011.

It is an arithmetic number, because the mean of its divisors is an integer number (531531).

Almost surely, 2^4391721 is an apocalyptic number.

It is an amenable number.

4391721 is a deficient number, since it is larger than the sum of its proper divisors (1986651).

4391721 is a wasteful number, since it uses less digits than its factorization.

4391721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2680 (or 2677 counting only the distinct ones).

The product of its digits is 1512, while the sum is 27.

The square root of 4391721 is about 2095.6433379752. The cubic root of 4391721 is about 163.7614144288.

The spelling of 4391721 in words is "four million, three hundred ninety-one thousand, seven hundred twenty-one".