21000212199971 has 2 divisors, whose sum is σ = 21000212199972. Its totient is φ = 21000212199970.

The previous prime is 21000212199893. The next prime is 21000212200043. The reversal of 21000212199971 is 17999121200012.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21000212199971 - 2¹⁰ = 21000212198947 is a prime.

It is not a weakly prime, because it can be changed into another prime (21000212193971) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10500106099985 + 10500106099986.

It is an arithmetic number, because the mean of its divisors is an integer number (10500106099986).

Almost surely, 2^{21000212199971} is an apocalyptic number.

21000212199971 is a deficient number, since it is larger than the sum of its proper divisors (1).

21000212199971 is an equidigital number, since it uses as much as digits as its factorization.

21000212199971 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 40824, while the sum is 44.

Adding to 21000212199971 its reverse (17999121200012), we get a palindrome (38999333399983).

The spelling of 21000212199971 in words is "twenty-one trillion, two hundred twelve million, one hundred ninety-nine thousand, nine hundred seventy-one".