13245721 has 8 divisors (see below), whose sum is σ = 13870080.
Its totient is φ = 12632592.
The previous prime is 13245709. The next prime is 13245731. The reversal of 13245721 is 12754231.
It is a happy number.
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 13245721 - 221 = 11148569 is a prime.
It is a Duffinian number.
It is not an unprimeable number, because it can be changed into a prime (13245731) 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 7 ways as a sum of consecutive naturals, for example, 345 + ... + 5158.
It is an arithmetic number, because the mean of its divisors is an integer number (1733760).
Almost surely, 213245721 is an apocalyptic number.
It is an amenable number.
13245721 is a deficient number, since it is larger than the sum of its proper divisors (624359).
13245721 is an equidigital number, since it uses as much as digits as its factorization.
13245721 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 5615.
The product of its digits is 1680, while the sum is 25.
The square root of 13245721 is about 3639.4671313257.
The cubic root of 13245721 is about 236.6056989905.
Adding to 13245721 its reverse (12754231), we get a palindrome (25999952).
The spelling of 13245721 in words is "thirteen million, two hundred forty-five thousand, seven hundred twenty-one".