21431220212 has 12 divisors (see below), whose sum is σ = 38032870176. Its totient is φ = 10564685880.

The previous prime is 21431220211. The next prime is 21431220227. The reversal of 21431220212 is 21202213412.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21431220211) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 37730738 + ... + 37731305.

It is an arithmetic number, because the mean of its divisors is an integer number (3169405848).

Almost surely, 2^21431220212 is an apocalyptic number.

It is an amenable number.

21431220212 is a deficient number, since it is larger than the sum of its proper divisors (16601649964).

21431220212 is a wasteful number, since it uses less digits than its factorization.

21431220212 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 75462118 (or 75462116 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 20.

Adding to 21431220212 its reverse (21202213412), we get a palindrome (42633433624).

The spelling of 21431220212 in words is "twenty-one billion, four hundred thirty-one million, two hundred twenty thousand, two hundred twelve".