13423721 has 8 divisors (see below), whose sum is σ = 13705224. Its totient is φ = 13144320.

The previous prime is 13423699. The next prime is 13423763. The reversal of 13423721 is 12732431.

13423721 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 384400 + 13039321 = 620^2 + 3611^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 13423721 - 2¹⁰ = 13422697 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (13423771) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 20231 + ... + 20883.

It is an arithmetic number, because the mean of its divisors is an integer number (1713153).

Almost surely, 2^13423721 is an apocalyptic number.

It is an amenable number.

13423721 is a deficient number, since it is larger than the sum of its proper divisors (281503).

13423721 is an equidigital number, since it uses as much as digits as its factorization.

13423721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1051.

The product of its digits is 1008, while the sum is 23.

The square root of 13423721 is about 3663.8396526049. The cubic root of 13423721 is about 237.6608461675.

The spelling of 13423721 in words is "thirteen million, four hundred twenty-three thousand, seven hundred twenty-one".