21213543305971 has 2 divisors, whose sum is σ = 21213543305972. Its totient is φ = 21213543305970.

The previous prime is 21213543305917. The next prime is 21213543305987. The reversal of 21213543305971 is 17950334531212.

Together with previous prime (21213543305917) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21213543305971 - 2⁹ = 21213543305459 is a prime.

It is not a weakly prime, because it can be changed into another prime (21213543345971) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10606771652985 + 10606771652986.

It is an arithmetic number, because the mean of its divisors is an integer number (10606771652986).

Almost surely, 2^{21213543305971} is an apocalyptic number.

21213543305971 is a deficient number, since it is larger than the sum of its proper divisors (1).

21213543305971 is an equidigital number, since it uses as much as digits as its factorization.

21213543305971 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 680400, while the sum is 46.

The spelling of 21213543305971 in words is "twenty-one trillion, two hundred thirteen billion, five hundred forty-three million, three hundred five thousand, nine hundred seventy-one".