21210312231 has 12 divisors (see below), whose sum is σ = 30669481752. Its totient is φ = 14125270896.

The previous prime is 21210312229. The next prime is 21210312241. The reversal of 21210312231 is 13221301212.

21210312231 is a `hidden beast` number, since 2 + 121 + 0 + 312 + 231 = 666.

It is not a de Polignac number, because 21210312231 - 2¹ = 21210312229 is a prime.

It is a super-2 number, since 2×21210312231² (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 (21210312241) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1235776 + ... + 1252821.

It is an arithmetic number, because the mean of its divisors is an integer number (2555790146).

Almost surely, 2^21210312231 is an apocalyptic number.

21210312231 is a deficient number, since it is larger than the sum of its proper divisors (9459169521).

21210312231 is a wasteful number, since it uses less digits than its factorization.

21210312231 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2489550 (or 2489547 counting only the distinct ones).

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

Adding to 21210312231 its reverse (13221301212), we get a palindrome (34431613443).

The spelling of 21210312231 in words is "twenty-one billion, two hundred ten million, three hundred twelve thousand, two hundred thirty-one".