21213220433 has 4 divisors (see below), whose sum is σ = 21216437760. Its totient is φ = 21210003108.

The previous prime is 21213220421. The next prime is 21213220439. The reversal of 21213220433 is 33402231212.

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 21213220433 - 2⁴ = 21213220417 is a prime.

It is a super-2 number, since 2×21213220433² (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 = 21213220399 and 21213220408.

It is not an unprimeable number, because it can be changed into a prime (21213220439) 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, 1598753 + ... + 1611966.

It is an arithmetic number, because the mean of its divisors is an integer number (5304109440).

Almost surely, 2^21213220433 is an apocalyptic number.

It is an amenable number.

21213220433 is a deficient number, since it is larger than the sum of its proper divisors (3217327).

21213220433 is an equidigital number, since it uses as much as digits as its factorization.

21213220433 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3217326.

The product of its (nonzero) digits is 1728, while the sum is 23.

Adding to 21213220433 its reverse (33402231212), we get a palindrome (54615451645).

The spelling of 21213220433 in words is "twenty-one billion, two hundred thirteen million, two hundred twenty thousand, four hundred thirty-three".