12320021 has 6 divisors (see below), whose sum is σ = 14331510. Its totient is φ = 10559976.

The previous prime is 12320017. The next prime is 12320023. The reversal of 12320021 is 12002321.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 7761796 + 4558225 = 2786^2 + 2135^2 .

It is not a de Polignac number, because 12320021 - 2² = 12320017 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a plaindrome in base 15.

It is a junction number, because it is equal to n+sod(n) for n = 12319984 and 12320011.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12320023) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 125666 + ... + 125763.

It is an arithmetic number, because the mean of its divisors is an integer number (2388585).

Almost surely, 2^12320021 is an apocalyptic number.

It is an amenable number.

12320021 is a deficient number, since it is larger than the sum of its proper divisors (2011489).

12320021 is an equidigital number, since it uses as much as digits as its factorization.

12320021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 251443 (or 251436 counting only the distinct ones).

The product of its (nonzero) digits is 24, while the sum is 11.

The square root of 12320021 is about 3509.9887464207. The cubic root of 12320021 is about 230.9602012855.

Adding to 12320021 its reverse (12002321), we get a palindrome (24322342).

The spelling of 12320021 in words is "twelve million, three hundred twenty thousand, twenty-one".