211705121 has 2 divisors, whose sum is σ = 211705122. Its totient is φ = 211705120.

The previous prime is 211705111. The next prime is 211705127. The reversal of 211705121 is 121507112.

It is a happy number.

211705121 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 161010721 + 50694400 = 12689^2 + 7120^2 .

It is a cyclic number.

It is not a de Polignac number, because 211705121 - 2⁶ = 211705057 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 211705093 and 211705102.

It is not a weakly prime, because it can be changed into another prime (211705127) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 105852560 + 105852561.

It is an arithmetic number, because the mean of its divisors is an integer number (105852561).

Almost surely, 2^211705121 is an apocalyptic number.

It is an amenable number.

211705121 is a deficient number, since it is larger than the sum of its proper divisors (1).

211705121 is an equidigital number, since it uses as much as digits as its factorization.

211705121 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 140, while the sum is 20.

The square root of 211705121 is about 14550.0900684497. The cubic root of 211705121 is about 595.9966076785.

The spelling of 211705121 in words is "two hundred eleven million, seven hundred five thousand, one hundred twenty-one".