21456220533 has 32 divisors (see below), whose sum is σ = 31484851200. Its totient is φ = 12889094400.

The previous prime is 21456220531. The next prime is 21456220547. The reversal of 21456220533 is 33502265412.

It is a happy number.

It is not a de Polignac number, because 21456220533 - 2¹ = 21456220531 is a prime.

It is a super-3 number, since 3×21456220533³ (a number of 32 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is a junction number, because it is equal to n+sod(n) for n = 21456220494 and 21456220503.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21456220531) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 4359448 + ... + 4364366.

It is an arithmetic number, because the mean of its divisors is an integer number (983901600).

Almost surely, 2^21456220533 is an apocalyptic number.

It is an amenable number.

21456220533 is a deficient number, since it is larger than the sum of its proper divisors (10028630667).

21456220533 is a wasteful number, since it uses less digits than its factorization.

21456220533 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6073.

The product of its (nonzero) digits is 43200, while the sum is 33.

Adding to 21456220533 its reverse (33502265412), we get a palindrome (54958485945).

The spelling of 21456220533 in words is "twenty-one billion, four hundred fifty-six million, two hundred twenty thousand, five hundred thirty-three".