210121200109 has 2 divisors, whose sum is σ = 210121200110. Its totient is φ = 210121200108.

The previous prime is 210121200097. The next prime is 210121200131. The reversal of 210121200109 is 901002121012.

It is a happy number.

210121200109 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 162413030025 + 47708170084 = 403005^2 + 218422^2 .

It is a cyclic number.

It is not a de Polignac number, because 210121200109 - 2⁵ = 210121200077 is a prime.

It is a super-2 number, since 2×210121200109² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (210121200139) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 105060600054 + 105060600055.

It is an arithmetic number, because the mean of its divisors is an integer number (105060600055).

Almost surely, 2^210121200109 is an apocalyptic number.

It is an amenable number.

210121200109 is a deficient number, since it is larger than the sum of its proper divisors (1).

210121200109 is an equidigital number, since it uses as much as digits as its factorization.

210121200109 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 72, while the sum is 19.

The spelling of 210121200109 in words is "two hundred ten billion, one hundred twenty-one million, two hundred thousand, one hundred nine".