21231200213221 has 2 divisors, whose sum is σ = 21231200213222. Its totient is φ = 21231200213220.

The previous prime is 21231200213147. The next prime is 21231200213233. The reversal of 21231200213221 is 12231200213212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15132839109025 + 6098361104196 = 3890095^2 + 2469486^2 .

It is a cyclic number.

It is not a de Polignac number, because 21231200213221 - 2¹⁵ = 21231200180453 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21231200213192 and 21231200213201.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21231200213261) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10615600106610 + 10615600106611.

It is an arithmetic number, because the mean of its divisors is an integer number (10615600106611).

Almost surely, 2^{21231200213221} is an apocalyptic number.

It is an amenable number.

21231200213221 is a deficient number, since it is larger than the sum of its proper divisors (1).

21231200213221 is an equidigital number, since it uses as much as digits as its factorization.

21231200213221 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 576, while the sum is 22.

Adding to 21231200213221 its reverse (12231200213212), we get a palindrome (33462400426433).

Subtracting from 21231200213221 its reverse (12231200213212), we obtain a palindrome (9000000000009).

The spelling of 21231200213221 in words is "twenty-one trillion, two hundred thirty-one billion, two hundred million, two hundred thirteen thousand, two hundred twenty-one".