13635721 has 8 divisors (see below), whose sum is σ = 15277824. Its totient is φ = 12060720.

The previous prime is 13635719. The next prime is 13635731. The reversal of 13635721 is 12753631.

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 13635721 - 2¹ = 13635719 is a prime.

It is a super-3 number, since 3×13635721³ (a number of 22 digits) contains 333 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 13635721.

It is not an unprimeable number, because it can be changed into a prime (13635701) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 16345 + ... + 17158.

It is an arithmetic number, because the mean of its divisors is an integer number (1909728).

Almost surely, 2^13635721 is an apocalyptic number.

13635721 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

13635721 is a deficient number, since it is larger than the sum of its proper divisors (1642103).

13635721 is a wasteful number, since it uses less digits than its factorization.

13635721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33551.

The product of its digits is 3780, while the sum is 28.

The square root of 13635721 is about 3692.6577149798. The cubic root of 13635721 is about 238.9054381020.

The spelling of 13635721 in words is "thirteen million, six hundred thirty-five thousand, seven hundred twenty-one".