13378721 has 2 divisors, whose sum is σ = 13378722. Its totient is φ = 13378720.

The previous prime is 13378697. The next prime is 13378727. The reversal of 13378721 is 12787331.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 10471696 + 2907025 = 3236^2 + 1705^2 .

It is an emirp because it is prime and its reverse (12787331) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 13378721 - 2¹⁴ = 13362337 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (13378727) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6689360 + 6689361.

It is an arithmetic number, because the mean of its divisors is an integer number (6689361).

Almost surely, 2^13378721 is an apocalyptic number.

It is an amenable number.

13378721 is a deficient number, since it is larger than the sum of its proper divisors (1).

13378721 is an equidigital number, since it uses as much as digits as its factorization.

13378721 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 7056, while the sum is 32.

The square root of 13378721 is about 3657.6933988512. The cubic root of 13378721 is about 237.3949807156.

The spelling of 13378721 in words is "thirteen million, three hundred seventy-eight thousand, seven hundred twenty-one".