13087721 has 2 divisors, whose sum is σ = 13087722. Its totient is φ = 13087720.

The previous prime is 13087709. The next prime is 13087727. The reversal of 13087721 is 12778031.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 13039321 + 48400 = 3611^2 + 220^2 .

It is a cyclic number.

It is not a de Polignac number, because 13087721 - 2¹⁸ = 12825577 is a prime.

It is not a weakly prime, because it can be changed into another prime (13087727) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6543860 + 6543861.

It is an arithmetic number, because the mean of its divisors is an integer number (6543861).

Almost surely, 2^13087721 is an apocalyptic number.

It is an amenable number.

13087721 is a deficient number, since it is larger than the sum of its proper divisors (1).

13087721 is an equidigital number, since it uses as much as digits as its factorization.

13087721 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2352, while the sum is 29.

The square root of 13087721 is about 3617.6955372170. The cubic root of 13087721 is about 235.6611590969.

The spelling of 13087721 in words is "thirteen million, eighty-seven thousand, seven hundred twenty-one".