21210332219981 has 2 divisors, whose sum is σ = 21210332219982. Its totient is φ = 21210332219980.

The previous prime is 21210332219971. The next prime is 21210332219983. The reversal of 21210332219981 is 18991223301212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20087346935881 + 1122985284100 = 4481891^2 + 1059710^2 .

It is a cyclic number.

It is not a de Polignac number, because 21210332219981 - 2¹⁴ = 21210332203597 is a prime.

It is a super-2 number, since 2×21210332219981² (a number of 27 digits) contains 22 as substring.

Together with 21210332219983, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21210332219983) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10605166109990 + 10605166109991.

It is an arithmetic number, because the mean of its divisors is an integer number (10605166109991).

Almost surely, 2^{21210332219981} is an apocalyptic number.

It is an amenable number.

21210332219981 is a deficient number, since it is larger than the sum of its proper divisors (1).

21210332219981 is an equidigital number, since it uses as much as digits as its factorization.

21210332219981 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 93312, while the sum is 44.

The spelling of 21210332219981 in words is "twenty-one trillion, two hundred ten billion, three hundred thirty-two million, two hundred nineteen thousand, nine hundred eighty-one".