21223210133621 has 2 divisors, whose sum is σ = 21223210133622. Its totient is φ = 21223210133620.

The previous prime is 21223210133557. The next prime is 21223210133641. The reversal of 21223210133621 is 12633101232212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20777059610596 + 446150523025 = 4558186^2 + 667945^2 .

It is a cyclic number.

It is not a de Polignac number, because 21223210133621 - 2⁶ = 21223210133557 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21223210133641) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10611605066810 + 10611605066811.

It is an arithmetic number, because the mean of its divisors is an integer number (10611605066811).

Almost surely, 2^{21223210133621} is an apocalyptic number.

It is an amenable number.

21223210133621 is a deficient number, since it is larger than the sum of its proper divisors (1).

21223210133621 is an equidigital number, since it uses as much as digits as its factorization.

21223210133621 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5184, while the sum is 29.

Adding to 21223210133621 its reverse (12633101232212), we get a palindrome (33856311365833).

The spelling of 21223210133621 in words is "twenty-one trillion, two hundred twenty-three billion, two hundred ten million, one hundred thirty-three thousand, six hundred twenty-one".