21203211231 has 12 divisors (see below), whose sum is σ = 31454614152. Its totient is φ = 13753434096.

The previous prime is 21203211229. The next prime is 21203211251. The reversal of 21203211231 is 13211230212.

21203211231 is a `hidden beast` number, since 21 + 203 + 211 + 231 = 666.

It is not a de Polignac number, because 21203211231 - 2¹ = 21203211229 is a prime.

It is a super-2 number, since 2×21203211231² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21203211221) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 31836321 + ... + 31836986.

It is an arithmetic number, because the mean of its divisors is an integer number (2621217846).

Almost surely, 2^21203211231 is an apocalyptic number.

21203211231 is a deficient number, since it is larger than the sum of its proper divisors (10251402921).

21203211231 is a wasteful number, since it uses less digits than its factorization.

21203211231 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 63673350 (or 63673347 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 18.

Adding to 21203211231 its reverse (13211230212), we get a palindrome (34414441443).

The spelling of 21203211231 in words is "twenty-one billion, two hundred three million, two hundred eleven thousand, two hundred thirty-one".