21243403234 has 16 divisors (see below), whose sum is σ = 32984635320. Its totient is φ = 10248985600.

The previous prime is 21243403213. The next prime is 21243403243. The reversal of 21243403234 is 43230434212.

It can be written as a sum of positive squares in 4 ways, for example, as 18822468025 + 2420935209 = 137195^2 + 49203^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 21529 + ... + 207244.

Almost surely, 2^21243403234 is an apocalyptic number.

21243403234 is a deficient number, since it is larger than the sum of its proper divisors (11741232086).

21243403234 is a wasteful number, since it uses less digits than its factorization.

21243403234 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 230405.

The product of its (nonzero) digits is 13824, while the sum is 28.

Adding to 21243403234 its reverse (43230434212), we get a palindrome (64473837446).

The spelling of 21243403234 in words is "twenty-one billion, two hundred forty-three million, four hundred three thousand, two hundred thirty-four".