21121443533 has 4 divisors (see below), whose sum is σ = 21287754240. Its totient is φ = 20955132828.

The previous prime is 21121443527. The next prime is 21121443557. The reversal of 21121443533 is 33534412112.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21121443533 - 2⁴ = 21121443517 is a prime.

It is a super-2 number, since 2×21121443533² (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 = 21121443496 and 21121443505.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21121442533) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 83155163 + ... + 83155416.

It is an arithmetic number, because the mean of its divisors is an integer number (5321938560).

Almost surely, 2^21121443533 is an apocalyptic number.

It is an amenable number.

21121443533 is a deficient number, since it is larger than the sum of its proper divisors (166310707).

21121443533 is a wasteful number, since it uses less digits than its factorization.

21121443533 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 166310706.

The product of its digits is 8640, while the sum is 29.

Adding to 21121443533 its reverse (33534412112), we get a palindrome (54655855645).

The spelling of 21121443533 in words is "twenty-one billion, one hundred twenty-one million, four hundred forty-three thousand, five hundred thirty-three".