821212211999 has 2 divisors, whose sum is σ = 821212212000. Its totient is φ = 821212211998.

The previous prime is 821212211977. The next prime is 821212212001. The reversal of 821212211999 is 999112212128.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-821212211999 is a prime.

Together with 821212212001, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (821212211909) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 410606105999 + 410606106000.

It is an arithmetic number, because the mean of its divisors is an integer number (410606106000).

Almost surely, 2^821212211999 is an apocalyptic number.

821212211999 is a deficient number, since it is larger than the sum of its proper divisors (1).

821212211999 is an equidigital number, since it uses as much as digits as its factorization.

821212211999 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 93312, while the sum is 47.

The spelling of 821212211999 in words is "eight hundred twenty-one billion, two hundred twelve million, two hundred eleven thousand, nine hundred ninety-nine".