12308721 has 4 divisors (see below), whose sum is σ = 16411632. Its totient is φ = 8205812.

The previous prime is 12308717. The next prime is 12308743. The reversal of 12308721 is 12780321.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 12780321 = 3 ⋅4260107.

It is a cyclic number.

It is not a de Polignac number, because 12308721 - 2² = 12308717 is a prime.

It is a super-2 number, since 2×12308721² = 303009225311682, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 12308691 and 12308700.

It is not an unprimeable number, because it can be changed into a prime (12308711) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2051451 + ... + 2051456.

It is an arithmetic number, because the mean of its divisors is an integer number (4102908).

Almost surely, 2^12308721 is an apocalyptic number.

It is an amenable number.

12308721 is a deficient number, since it is larger than the sum of its proper divisors (4102911).

12308721 is an equidigital number, since it uses as much as digits as its factorization.

12308721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4102910.

The product of its (nonzero) digits is 672, while the sum is 24.

The square root of 12308721 is about 3508.3786853759. The cubic root of 12308721 is about 230.8895669740.

The spelling of 12308721 in words is "twelve million, three hundred eight thousand, seven hundred twenty-one".