13018721 has 4 divisors (see below), whose sum is σ = 13033152. Its totient is φ = 13004292.

The previous prime is 13018717. The next prime is 13018727. The reversal of 13018721 is 12781031.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 12781031 = 23 ⋅555697.

It is a cyclic number.

It is not a de Polignac number, because 13018721 - 2² = 13018717 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (13018727) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5765 + ... + 7698.

It is an arithmetic number, because the mean of its divisors is an integer number (3258288).

Almost surely, 2^13018721 is an apocalyptic number.

It is an amenable number.

13018721 is a deficient number, since it is larger than the sum of its proper divisors (14431).

13018721 is an equidigital number, since it uses as much as digits as its factorization.

13018721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14430.

The product of its (nonzero) digits is 336, while the sum is 23.

The square root of 13018721 is about 3608.1464770710. The cubic root of 13018721 is about 235.2462847289.

Adding to 13018721 its reverse (12781031), we get a palindrome (25799752).

The spelling of 13018721 in words is "thirteen million, eighteen thousand, seven hundred twenty-one".