21211221992 has 32 divisors (see below), whose sum is σ = 41466470400. Its totient is φ = 10159257024.

The previous prime is 21211221991. The next prime is 21211222051. The reversal of 21211221992 is 29912211212.

It is not an unprimeable number, because it can be changed into a prime (21211221991) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 330488 + ... + 389415.

It is an arithmetic number, because the mean of its divisors is an integer number (1295827200).

Almost surely, 2^21211221992 is an apocalyptic number.

It is an amenable number.

21211221992 is a deficient number, since it is larger than the sum of its proper divisors (20255248408).

21211221992 is a wasteful number, since it uses less digits than its factorization.

21211221992 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 720065 (or 720061 counting only the distinct ones).

The product of its digits is 2592, while the sum is 32.

The spelling of 21211221992 in words is "twenty-one billion, two hundred eleven million, two hundred twenty-one thousand, nine hundred ninety-two".