21111021201671 has 2 divisors, whose sum is σ = 21111021201672. Its totient is φ = 21111021201670.

The previous prime is 21111021201653. The next prime is 21111021201701. The reversal of 21111021201671 is 17610212011112.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21111021201671 - 2⁴² = 16712974690567 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21111021201671.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21111021201601) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10555510600835 + 10555510600836.

It is an arithmetic number, because the mean of its divisors is an integer number (10555510600836).

Almost surely, 2^{21111021201671} is an apocalyptic number.

21111021201671 is a deficient number, since it is larger than the sum of its proper divisors (1).

21111021201671 is an equidigital number, since it uses as much as digits as its factorization.

21111021201671 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 336, while the sum is 26.

Adding to 21111021201671 its reverse (17610212011112), we get a palindrome (38721233212783).

The spelling of 21111021201671 in words is "twenty-one trillion, one hundred eleven billion, twenty-one million, two hundred one thousand, six hundred seventy-one".