12721999 has 2 divisors, whose sum is σ = 12722000. Its totient is φ = 12721998.

The previous prime is 12721939. The next prime is 12722009. The reversal of 12721999 is 99912721.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 12721999 - 2²³ = 4333391 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (12721939) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6360999 + 6361000.

It is an arithmetic number, because the mean of its divisors is an integer number (6361000).

Almost surely, 2^12721999 is an apocalyptic number.

12721999 is a deficient number, since it is larger than the sum of its proper divisors (1).

12721999 is an equidigital number, since it uses as much as digits as its factorization.

12721999 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 20412, while the sum is 40.

The square root of 12721999 is about 3566.7911348998. The cubic root of 12721999 is about 233.4452916229.

The spelling of 12721999 in words is "twelve million, seven hundred twenty-one thousand, nine hundred ninety-nine".