12423444021 has 6 divisors (see below), whose sum is σ = 17944974710. Its totient is φ = 8282296008.

The previous prime is 12423444013. The next prime is 12423444023. The reversal of 12423444021 is 12044432421.

12423444021 is a `hidden beast` number, since 1 + 24 + 234 + 4 + 402 + 1 = 666.

It can be written as a sum of positive squares in only one way, i.e., 7252395921 + 5171048100 = 85161^2 + 71910^2 .

It is not a de Polignac number, because 12423444021 - 2³ = 12423444013 is a prime.

It is a super-2 number, since 2×12423444021² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12423444023) 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, 690191326 + ... + 690191343.

Almost surely, 2^12423444021 is an apocalyptic number.

It is an amenable number.

12423444021 is a deficient number, since it is larger than the sum of its proper divisors (5521530689).

12423444021 is a wasteful number, since it uses less digits than its factorization.

12423444021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1380382675 (or 1380382672 counting only the distinct ones).

The product of its (nonzero) digits is 6144, while the sum is 27.

Adding to 12423444021 its reverse (12044432421), we get a palindrome (24467876442).

The spelling of 12423444021 in words is "twelve billion, four hundred twenty-three million, four hundred forty-four thousand, twenty-one".