21121202221 has 8 divisors (see below), whose sum is σ = 24171453824. Its totient is φ = 18079184880.

The previous prime is 21121202177. The next prime is 21121202279. The reversal of 21121202221 is 12220212112.

It is a happy number.

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 21121202221 - 2¹⁵ = 21121169453 is a prime.

It is a super-3 number, since 3×21121202221³ (a number of 32 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a junction number, because it is equal to n+sod(n) for n = 21121202195 and 21121202204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21121202281) 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, 2053065 + ... + 2063326.

It is an arithmetic number, because the mean of its divisors is an integer number (3021431728).

Almost surely, 2^21121202221 is an apocalyptic number.

It is an amenable number.

21121202221 is a deficient number, since it is larger than the sum of its proper divisors (3050251603).

21121202221 is an equidigital number, since it uses as much as digits as its factorization.

21121202221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4117131.

The product of its (nonzero) digits is 64, while the sum is 16.

Adding to 21121202221 its reverse (12220212112), we get a palindrome (33341414333).

The spelling of 21121202221 in words is "twenty-one billion, one hundred twenty-one million, two hundred two thousand, two hundred twenty-one".