211243240921 has 2 divisors, whose sum is σ = 211243240922. Its totient is φ = 211243240920.

The previous prime is 211243240913. The next prime is 211243240933. The reversal of 211243240921 is 129042342112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 197709176025 + 13534064896 = 444645^2 + 116336^2 .

It is a cyclic number.

It is not a de Polignac number, because 211243240921 - 2³ = 211243240913 is a prime.

It is not a weakly prime, because it can be changed into another prime (211243244921) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 105621620460 + 105621620461.

It is an arithmetic number, because the mean of its divisors is an integer number (105621620461).

Almost surely, 2^211243240921 is an apocalyptic number.

It is an amenable number.

211243240921 is a deficient number, since it is larger than the sum of its proper divisors (1).

211243240921 is an equidigital number, since it uses as much as digits as its factorization.

211243240921 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 6912, while the sum is 31.

The spelling of 211243240921 in words is "two hundred eleven billion, two hundred forty-three million, two hundred forty thousand, nine hundred twenty-one".