13251721 has 16 divisors (see below), whose sum is σ = 16882560. Its totient is φ = 10126080.

The previous prime is 13251709. The next prime is 13251727. The reversal of 13251721 is 12715231.

It is a happy number.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-13251721 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 13251692 and 13251701.

It is not an unprimeable number, because it can be changed into a prime (13251727) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 670 + ... + 5191.

It is an arithmetic number, because the mean of its divisors is an integer number (1055160).

Almost surely, 2^13251721 is an apocalyptic number.

It is an amenable number.

13251721 is a deficient number, since it is larger than the sum of its proper divisors (3630839).

13251721 is a wasteful number, since it uses less digits than its factorization.

13251721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5904.

The product of its digits is 420, while the sum is 22.

The square root of 13251721 is about 3640.2913344951. The cubic root of 13251721 is about 236.6414192027.

Adding to 13251721 its reverse (12715231), we get a palindrome (25966952).

The spelling of 13251721 in words is "thirteen million, two hundred fifty-one thousand, seven hundred twenty-one".