21213560223181 has 2 divisors, whose sum is σ = 21213560223182. Its totient is φ = 21213560223180.

The previous prime is 21213560223143. The next prime is 21213560223209. The reversal of 21213560223181 is 18132206531212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21069660628900 + 143899594281 = 4590170^2 + 379341^2 .

It is a cyclic number.

It is not a de Polignac number, because 21213560223181 - 2²⁵ = 21213526668749 is a prime.

It is a super-2 number, since 2×21213560223181² (a number of 27 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21213560223181.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21213560221181) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10606780111590 + 10606780111591.

It is an arithmetic number, because the mean of its divisors is an integer number (10606780111591).

Almost surely, 2^{21213560223181} is an apocalyptic number.

It is an amenable number.

21213560223181 is a deficient number, since it is larger than the sum of its proper divisors (1).

21213560223181 is an equidigital number, since it uses as much as digits as its factorization.

21213560223181 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 34560, while the sum is 37.

Adding to 21213560223181 its reverse (18132206531212), we get a palindrome (39345766754393).

The spelling of 21213560223181 in words is "twenty-one trillion, two hundred thirteen billion, five hundred sixty million, two hundred twenty-three thousand, one hundred eighty-one".