4279721 has 4 divisors (see below), whose sum is σ = 4287444. Its totient is φ = 4272000.

The previous prime is 4279687. The next prime is 4279741. The reversal of 4279721 is 1279724.

Added to its reverse (1279724) it gives a triangular number (5559445 = T₃₃₃₄).

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 1590121 + 2689600 = 1261^2 + 1640^2 .

It is a cyclic number.

It is not a de Polignac number, because 4279721 - 2⁶ = 4279657 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (4279741) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2960 + ... + 4161.

It is an arithmetic number, because the mean of its divisors is an integer number (1071861).

Almost surely, 2^4279721 is an apocalyptic number.

It is an amenable number.

4279721 is a deficient number, since it is larger than the sum of its proper divisors (7723).

4279721 is an equidigital number, since it uses as much as digits as its factorization.

4279721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7722.

The product of its digits is 7056, while the sum is 32.

The square root of 4279721 is about 2068.7486555887. The cubic root of 4279721 is about 162.3572995755.

Adding to 4279721 its reverse (1279724), we get a triangular number (5559445 = T₃₃₃₄).

The spelling of 4279721 in words is "four million, two hundred seventy-nine thousand, seven hundred twenty-one".