21243004234 has 8 divisors (see below), whose sum is σ = 32301006660. Its totient is φ = 10476002016.

The previous prime is 21243004219. The next prime is 21243004241. The reversal of 21243004234 is 43240034212.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 19056974209 + 2186030025 = 138047^2 + 46755^2 .

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

It is a junction number, because it is equal to n+sod(n) for n = 21243004199 and 21243004208.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 72749869 + ... + 72750160.

Almost surely, 2^21243004234 is an apocalyptic number.

21243004234 is a deficient number, since it is larger than the sum of its proper divisors (11058002426).

21243004234 is a wasteful number, since it uses less digits than its factorization.

21243004234 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 145500104.

The product of its (nonzero) digits is 4608, while the sum is 25.

Adding to 21243004234 its reverse (43240034212), we get a palindrome (64483038446).

The spelling of 21243004234 in words is "twenty-one billion, two hundred forty-three million, four thousand, two hundred thirty-four".