12787721 has 2 divisors, whose sum is σ = 12787722. Its totient is φ = 12787720.

The previous prime is 12787693. The next prime is 12787763. The reversal of 12787721 is 12778721.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 10725625 + 2062096 = 3275^2 + 1436^2 .

It is a cyclic number.

It is not a de Polignac number, because 12787721 - 2¹⁴ = 12771337 is a prime.

It is not a weakly prime, because it can be changed into another prime (12787781) 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 as a sum of consecutive naturals, namely, 6393860 + 6393861.

It is an arithmetic number, because the mean of its divisors is an integer number (6393861).

Almost surely, 2^12787721 is an apocalyptic number.

It is an amenable number.

12787721 is a deficient number, since it is larger than the sum of its proper divisors (1).

12787721 is an equidigital number, since it uses as much as digits as its factorization.

12787721 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 10976, while the sum is 35.

The square root of 12787721 is about 3575.9923098351. The cubic root of 12787721 is about 233.8465950970.

The spelling of 12787721 in words is "twelve million, seven hundred eighty-seven thousand, seven hundred twenty-one".