12721939 has 2 divisors, whose sum is σ = 12721940. Its totient is φ = 12721938.

The previous prime is 12721903. The next prime is 12721999. The reversal of 12721939 is 93912721.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 12721939 - 2¹¹ = 12719891 is a prime.

It is not a weakly prime, because it can be changed into another prime (12721999) 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, 6360969 + 6360970.

It is an arithmetic number, because the mean of its divisors is an integer number (6360970).

Almost surely, 2^12721939 is an apocalyptic number.

12721939 is a deficient number, since it is larger than the sum of its proper divisors (1).

12721939 is an equidigital number, since it uses as much as digits as its factorization.

12721939 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 6804, while the sum is 34.

The square root of 12721939 is about 3566.7827239685. The cubic root of 12721939 is about 233.4449246277. Note that the first 3 decimals are identical.

The spelling of 12721939 in words is "twelve million, seven hundred twenty-one thousand, nine hundred thirty-nine".