13287321 has 20 divisors (see below), whose sum is σ = 20338164. Its totient is φ = 8640000.

The previous prime is 13287317. The next prime is 13287341. The reversal of 13287321 is 12378231.

It can be written as a sum of positive squares in 2 ways, for example, as 585225 + 12702096 = 765^2 + 3564^2 .

It is not a de Polignac number, because 13287321 - 2² = 13287317 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (13287311) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 1321 + ... + 5321.

Almost surely, 2^13287321 is an apocalyptic number.

It is an amenable number.

13287321 is a deficient number, since it is larger than the sum of its proper divisors (7050843).

13287321 is an equidigital number, since it uses as much as digits as its factorization.

13287321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4054 (or 4045 counting only the distinct ones).

The product of its digits is 2016, while the sum is 27.

The square root of 13287321 is about 3645.1777734426. The cubic root of 13287321 is about 236.8531376615.

It can be divided in two parts, 1328 and 7321, that added together give a square (8649 = 93²).

The spelling of 13287321 in words is "thirteen million, two hundred eighty-seven thousand, three hundred twenty-one".