21121201232221 has 8 divisors (see below), whose sum is σ = 21315547134200. Its totient is φ = 20926865756160.

The previous prime is 21121201232213. The next prime is 21121201232251. The reversal of 21121201232221 is 12223210212112.

It can be written as a sum of positive squares in 4 ways, for example, as 8420965572100 + 12700235660121 = 2901890^2 + 3563739^2 .

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 21121201232221 - 2³ = 21121201232213 is a prime.

It is a super-2 number, since 2×21121201232221² (a number of 27 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 = 21121201232192 and 21121201232201.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21121201232251) 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, 1493365 + ... + 6668773.

It is an arithmetic number, because the mean of its divisors is an integer number (2664443391775).

Almost surely, 2^{21121201232221} is an apocalyptic number.

It is an amenable number.

21121201232221 is a deficient number, since it is larger than the sum of its proper divisors (194345901979).

21121201232221 is a wasteful number, since it uses less digits than its factorization.

21121201232221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5212959.

The product of its (nonzero) digits is 384, while the sum is 22.

Adding to 21121201232221 its reverse (12223210212112), we get a palindrome (33344411444333).

The spelling of 21121201232221 in words is "twenty-one trillion, one hundred twenty-one billion, two hundred one million, two hundred thirty-two thousand, two hundred twenty-one".