13071721 has 8 divisors (see below), whose sum is σ = 14563080. Its totient is φ = 11649792.

The previous prime is 13071689. The next prime is 13071731. The reversal of 13071721 is 12717031.

It can be written as a sum of positive squares in 4 ways, for example, as 32400 + 13039321 = 180^2 + 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 13071721 - 2⁵ = 13071689 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 13071692 and 13071701.

It is not an unprimeable number, because it can be changed into a prime (13071731) 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, 16960 + ... + 17713.

It is an arithmetic number, because the mean of its divisors is an integer number (1820385).

Almost surely, 2^13071721 is an apocalyptic number.

It is an amenable number.

13071721 is a deficient number, since it is larger than the sum of its proper divisors (1491359).

13071721 is a wasteful number, since it uses less digits than its factorization.

13071721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 34715.

The product of its (nonzero) digits is 294, while the sum is 22.

The square root of 13071721 is about 3615.4835084674. The cubic root of 13071721 is about 235.5650864467.

Adding to 13071721 its reverse (12717031), we get a palindrome (25788752).

The spelling of 13071721 in words is "thirteen million, seventy-one thousand, seven hundred twenty-one".