12721979 has 4 divisors (see below), whose sum is σ = 12840984. Its totient is φ = 12602976.

The previous prime is 12721939. The next prime is 12721999. The reversal of 12721979 is 97912721.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 12721979 - 2¹⁶ = 12656443 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a 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 in 3 ways as a sum of consecutive naturals, for example, 59342 + ... + 59555.

It is an arithmetic number, because the mean of its divisors is an integer number (3210246).

Almost surely, 2^12721979 is an apocalyptic number.

12721979 is a deficient number, since it is larger than the sum of its proper divisors (119005).

12721979 is a wasteful number, since it uses less digits than its factorization.

12721979 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 119004.

The product of its digits is 15876, while the sum is 38.

The square root of 12721979 is about 3566.7883312582. The cubic root of 12721979 is about 233.4451692913.

The spelling of 12721979 in words is "twelve million, seven hundred twenty-one thousand, nine hundred seventy-nine".