12381021 has 6 divisors (see below), whose sum is σ = 17883710. Its totient is φ = 8254008.

The previous prime is 12381011. The next prime is 12381023. The reversal of 12381021 is 12018321.

It can be written as a sum of positive squares in only one way, i.e., 11148921 + 1232100 = 3339^2 + 1110^2 .

It is not a de Polignac number, because 12381021 - 2⁶ = 12380957 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 12380985 and 12381003.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12381023) 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, 687826 + ... + 687843.

Almost surely, 2^12381021 is an apocalyptic number.

It is an amenable number.

12381021 is a deficient number, since it is larger than the sum of its proper divisors (5502689).

12381021 is a wasteful number, since it uses less digits than its factorization.

12381021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1375675 (or 1375672 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 18.

The square root of 12381021 is about 3518.6675034734. The cubic root of 12381021 is about 231.3407575585.

Adding to 12381021 its reverse (12018321), we get a palindrome (24399342).

The spelling of 12381021 in words is "twelve million, three hundred eighty-one thousand, twenty-one".