21155104213 has 2 divisors, whose sum is σ = 21155104214. Its totient is φ = 21155104212.

The previous prime is 21155104199. The next prime is 21155104231. The reversal of 21155104213 is 31240155112.

Together with next prime (21155104231) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19403932804 + 1751171409 = 139298^2 + 41847^2 .

It is a cyclic number.

It is not a de Polignac number, because 21155104213 - 2²⁵ = 21121549781 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21155134213) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10577552106 + 10577552107.

It is an arithmetic number, because the mean of its divisors is an integer number (10577552107).

Almost surely, 2^21155104213 is an apocalyptic number.

It is an amenable number.

21155104213 is a deficient number, since it is larger than the sum of its proper divisors (1).

21155104213 is an equidigital number, since it uses as much as digits as its factorization.

21155104213 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1200, while the sum is 25.

Adding to 21155104213 its reverse (31240155112), we get a palindrome (52395259325).

The spelling of 21155104213 in words is "twenty-one billion, one hundred fifty-five million, one hundred four thousand, two hundred thirteen".