12791721 has 8 divisors (see below), whose sum is σ = 17076064. Its totient is φ = 8517600.

The previous prime is 12791687. The next prime is 12791773. The reversal of 12791721 is 12719721.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 12791721 - 2⁷ = 12791593 is a prime.

It is a super-2 number, since 2×12791721² = 327256252283682, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (12791621) 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 7 ways as a sum of consecutive naturals, for example, 1125 + ... + 5181.

It is an arithmetic number, because the mean of its divisors is an integer number (2134508).

Almost surely, 2^12791721 is an apocalyptic number.

It is an amenable number.

12791721 is a deficient number, since it is larger than the sum of its proper divisors (4284343).

12791721 is a wasteful number, since it uses less digits than its factorization.

12791721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5111.

The product of its digits is 1764, while the sum is 30.

The square root of 12791721 is about 3576.5515514249. The cubic root of 12791721 is about 233.8709749655.

The spelling of 12791721 in words is "twelve million, seven hundred ninety-one thousand, seven hundred twenty-one".