21101033331221 has 4 divisors (see below), whose sum is σ = 21159810583200. Its totient is φ = 21042256079244.

The previous prime is 21101033331197. The next prime is 21101033331251. The reversal of 21101033331221 is 12213333010112.

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 a de Polignac number, because none of the positive numbers 2^k-21101033331221 is a prime.

It is a super-2 number, since 2×21101033331221² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21101033331251) 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, 29388625451 + ... + 29388626168.

It is an arithmetic number, because the mean of its divisors is an integer number (5289952645800).

Almost surely, 2^{21101033331221} is an apocalyptic number.

It is an amenable number.

21101033331221 is a deficient number, since it is larger than the sum of its proper divisors (58777251979).

21101033331221 is an equidigital number, since it uses as much as digits as its factorization.

21101033331221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 58777251978.

The product of its (nonzero) digits is 648, while the sum is 23.

Adding to 21101033331221 its reverse (12213333010112), we get a palindrome (33314366341333).

The spelling of 21101033331221 in words is "twenty-one trillion, one hundred one billion, thirty-three million, three hundred thirty-one thousand, two hundred twenty-one".