21311223533 has 8 divisors (see below), whose sum is σ = 22049275680. Its totient is φ = 20573383600.

The previous prime is 21311223509. The next prime is 21311223559. The reversal of 21311223533 is 33532211312.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21311223533 - 2¹² = 21311219437 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21311223503) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 166766 + ... + 265392.

It is an arithmetic number, because the mean of its divisors is an integer number (2756159460).

Almost surely, 2^21311223533 is an apocalyptic number.

It is an amenable number.

21311223533 is a deficient number, since it is larger than the sum of its proper divisors (738052147).

21311223533 is an equidigital number, since it uses as much as digits as its factorization.

21311223533 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 106107.

The product of its digits is 3240, while the sum is 26.

Adding to 21311223533 its reverse (33532211312), we get a palindrome (54843434845).

The spelling of 21311223533 in words is "twenty-one billion, three hundred eleven million, two hundred twenty-three thousand, five hundred thirty-three".