13788721 has 2 divisors, whose sum is σ = 13788722. Its totient is φ = 13788720.

The previous prime is 13788703. The next prime is 13788763. The reversal of 13788721 is 12788731.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 7840000 + 5948721 = 2800^2 + 2439^2 .

It is a cyclic number.

It is not a de Polignac number, because 13788721 - 2¹¹ = 13786673 is a prime.

It is equal to p₈₉₇₂₅₆ and since 13788721 and 897256 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (13788701) 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 as a sum of consecutive naturals, namely, 6894360 + 6894361.

It is an arithmetic number, because the mean of its divisors is an integer number (6894361).

Almost surely, 2^13788721 is an apocalyptic number.

It is an amenable number.

13788721 is a deficient number, since it is larger than the sum of its proper divisors (1).

13788721 is an equidigital number, since it uses as much as digits as its factorization.

13788721 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 18816, while the sum is 37.

The square root of 13788721 is about 3713.3167115128. The cubic root of 13788721 is about 239.7956652001.

The spelling of 13788721 in words is "thirteen million, seven hundred eighty-eight thousand, seven hundred twenty-one".