21533213331 has 12 divisors (see below), whose sum is σ = 35546891952. Its totient is φ = 12304693296.

The previous prime is 21533213311. The next prime is 21533213333. The reversal of 21533213331 is 13331233512.

21533213331 is a `hidden beast` number, since 2 + 1 + 5 + 3 + 321 + 3 + 331 = 666.

It is not a de Polignac number, because 21533213331 - 2¹⁴ = 21533196947 is a prime.

It is a super-2 number, since 2×21533213331² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21533213295 and 21533213304.

It is not an unprimeable number, because it can be changed into a prime (21533213333) 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, 170898456 + ... + 170898581.

It is an arithmetic number, because the mean of its divisors is an integer number (2962240996).

Almost surely, 2^21533213331 is an apocalyptic number.

21533213331 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

21533213331 is a deficient number, since it is larger than the sum of its proper divisors (14013678621).

21533213331 is a wasteful number, since it uses less digits than its factorization.

21533213331 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 341797050 (or 341797047 counting only the distinct ones).

The product of its digits is 4860, while the sum is 27.

Adding to 21533213331 its reverse (13331233512), we get a palindrome (34864446843).

The spelling of 21533213331 in words is "twenty-one billion, five hundred thirty-three million, two hundred thirteen thousand, three hundred thirty-one".