211121000021 has 2 divisors, whose sum is σ = 211121000022. Its totient is φ = 211121000020.

The previous prime is 211120999871. The next prime is 211121000029. The reversal of 211121000021 is 120000121112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 205471824100 + 5649175921 = 453290^2 + 75161^2 .

It is a cyclic number.

It is not a de Polignac number, because 211121000021 - 2²⁶ = 211053891157 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 211120999966 and 211121000011.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (211121000029) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 105560500010 + 105560500011.

It is an arithmetic number, because the mean of its divisors is an integer number (105560500011).

Almost surely, 2^211121000021 is an apocalyptic number.

It is an amenable number.

211121000021 is a deficient number, since it is larger than the sum of its proper divisors (1).

211121000021 is an equidigital number, since it uses as much as digits as its factorization.

211121000021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 8, while the sum is 11.

Adding to 211121000021 its reverse (120000121112), we get a palindrome (331121121133).

The spelling of 211121000021 in words is "two hundred eleven billion, one hundred twenty-one million, twenty-one", and thus it is an aban number.