21311455533 has 24 divisors (see below), whose sum is σ = 29469037728. Its totient is φ = 13699011648.

The previous prime is 21311455523. The next prime is 21311455541. The reversal of 21311455533 is 33555411312.

It is not a de Polignac number, because 21311455533 - 2²¹ = 21309358381 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21311455494 and 21311455503.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21311455513) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1980235 + ... + 1990967.

It is an arithmetic number, because the mean of its divisors is an integer number (1227876572).

Almost surely, 2^21311455533 is an apocalyptic number.

It is an amenable number.

21311455533 is a deficient number, since it is larger than the sum of its proper divisors (8157582195).

21311455533 is a wasteful number, since it uses less digits than its factorization.

21311455533 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11581 (or 11552 counting only the distinct ones).

The product of its digits is 27000, while the sum is 33.

Adding to 21311455533 its reverse (33555411312), we get a palindrome (54866866845).

The spelling of 21311455533 in words is "twenty-one billion, three hundred eleven million, four hundred fifty-five thousand, five hundred thirty-three".