21031220233 has 4 divisors (see below), whose sum is σ = 21160246288. Its totient is φ = 20902194180.

The previous prime is 21031220219. The next prime is 21031220257. The reversal of 21031220233 is 33202213012.

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 21031220233 - 2⁵ = 21031220201 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21031220233.

It is not an unprimeable number, because it can be changed into a prime (21031220293) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 64512783 + ... + 64513108.

It is an arithmetic number, because the mean of its divisors is an integer number (5290061572).

Almost surely, 2^21031220233 is an apocalyptic number.

It is an amenable number.

21031220233 is a deficient number, since it is larger than the sum of its proper divisors (129026055).

21031220233 is a wasteful number, since it uses less digits than its factorization.

21031220233 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 129026054.

The product of its (nonzero) digits is 432, while the sum is 19.

Adding to 21031220233 its reverse (33202213012), we get a palindrome (54233433245).

The spelling of 21031220233 in words is "twenty-one billion, thirty-one million, two hundred twenty thousand, two hundred thirty-three".