21111033221 has 8 divisors (see below), whose sum is σ = 21299679000. Its totient is φ = 20922888448.

The previous prime is 21111033191. The next prime is 21111033233. The reversal of 21111033221 is 12233011112.

It can be written as a sum of positive squares in 4 ways, for example, as 197824225 + 20913208996 = 14065^2 + 144614^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21111033221 - 2²⁶ = 21043924357 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 21111033221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21111033271) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 40346 + ... + 209403.

It is an arithmetic number, because the mean of its divisors is an integer number (2662459875).

Almost surely, 2^21111033221 is an apocalyptic number.

It is an amenable number.

21111033221 is a deficient number, since it is larger than the sum of its proper divisors (188645779).

21111033221 is a wasteful number, since it uses less digits than its factorization.

21111033221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 250503.

The product of its (nonzero) digits is 72, while the sum is 17.

Adding to 21111033221 its reverse (12233011112), we get a palindrome (33344044333).

The spelling of 21111033221 in words is "twenty-one billion, one hundred eleven million, thirty-three thousand, two hundred twenty-one".