211821549659987 has 2 divisors, whose sum is σ = 211821549659988. Its totient is φ = 211821549659986.

The previous prime is 211821549659971. The next prime is 211821549660089. The reversal of 211821549659987 is 789956945128112.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 211821549659987 - 2⁴ = 211821549659971 is a prime.

It is not a weakly prime, because it can be changed into another prime (211821549619987) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 105910774829993 + 105910774829994.

It is an arithmetic number, because the mean of its divisors is an integer number (105910774829994).

Almost surely, 2^{211821549659987} is an apocalyptic number.

211821549659987 is a deficient number, since it is larger than the sum of its proper divisors (1).

211821549659987 is an equidigital number, since it uses as much as digits as its factorization.

211821549659987 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 783820800, while the sum is 77.

The spelling of 211821549659987 in words is "two hundred eleven trillion, eight hundred twenty-one billion, five hundred forty-nine million, six hundred fifty-nine thousand, nine hundred eighty-seven".