21243012124 has 12 divisors (see below), whose sum is σ = 37467990784. Its totient is φ = 10537871904.

The previous prime is 21243012103. The next prime is 21243012181. The reversal of 21243012124 is 42121034212.

It is a junction number, because it is equal to n+sod(n) for n = 21243012095 and 21243012104.

It is a congruent number.

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, 20907969 + ... + 20908984.

Almost surely, 2^21243012124 is an apocalyptic number.

It is an amenable number.

21243012124 is a deficient number, since it is larger than the sum of its proper divisors (16224978660).

21243012124 is a wasteful number, since it uses less digits than its factorization.

21243012124 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 41817084 (or 41817082 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 22.

Adding to 21243012124 its reverse (42121034212), we get a palindrome (63364046336).

The spelling of 21243012124 in words is "twenty-one billion, two hundred forty-three million, twelve thousand, one hundred twenty-four".