21213301231 has 4 divisors (see below), whose sum is σ = 21730698864. Its totient is φ = 20695903600.

The previous prime is 21213301229. The next prime is 21213301253. The reversal of 21213301231 is 13210331212.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21213301231 - 2¹ = 21213301229 is a prime.

It is a super-2 number, since 2×21213301231² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21213301199 and 21213301208.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21213301531) 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 3 ways as a sum of consecutive naturals, for example, 258698755 + ... + 258698836.

It is an arithmetic number, because the mean of its divisors is an integer number (5432674716).

Almost surely, 2^21213301231 is an apocalyptic number.

21213301231 is a deficient number, since it is larger than the sum of its proper divisors (517397633).

21213301231 is an equidigital number, since it uses as much as digits as its factorization.

21213301231 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 517397632.

The product of its (nonzero) digits is 216, while the sum is 19.

Adding to 21213301231 its reverse (13210331212), we get a palindrome (34423632443).

The spelling of 21213301231 in words is "twenty-one billion, two hundred thirteen million, three hundred one thousand, two hundred thirty-one".