21420423212 has 12 divisors (see below), whose sum is σ = 37496683896. Its totient is φ = 10707084960.

The previous prime is 21420423191. The next prime is 21420423223. The reversal of 21420423212 is 21232402412.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 766214 + ... + 793677.

It is an arithmetic number, because the mean of its divisors is an integer number (3124723658).

Almost surely, 2^21420423212 is an apocalyptic number.

It is an amenable number.

21420423212 is a deficient number, since it is larger than the sum of its proper divisors (16076260684).

21420423212 is a wasteful number, since it uses less digits than its factorization.

21420423212 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1563328 (or 1563326 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 23.

Adding to 21420423212 its reverse (21232402412), we get a palindrome (42652825624).

The spelling of 21420423212 in words is "twenty-one billion, four hundred twenty million, four hundred twenty-three thousand, two hundred twelve".