210121217 has 2 divisors, whose sum is σ = 210121218. Its totient is φ = 210121216.

The previous prime is 210121199. The next prime is 210121259. The reversal of 210121217 is 712121012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 209931121 + 190096 = 14489^2 + 436^2 .

It is a cyclic number.

It is not a de Polignac number, because 210121217 - 2¹⁰ = 210120193 is a prime.

It is a super-2 number, since 2×210121217² = 88301851667122178, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 210121195 and 210121204.

It is not a weakly prime, because it can be changed into another prime (210121297) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 105060608 + 105060609.

It is an arithmetic number, because the mean of its divisors is an integer number (105060609).

Almost surely, 2^210121217 is an apocalyptic number.

It is an amenable number.

210121217 is a deficient number, since it is larger than the sum of its proper divisors (1).

210121217 is an equidigital number, since it uses as much as digits as its factorization.

210121217 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 56, while the sum is 17.

The square root of 210121217 is about 14495.5585266660. The cubic root of 210121217 is about 594.5065390543.

Adding to 210121217 its reverse (712121012), we get a palindrome (922242229).

The spelling of 210121217 in words is "two hundred ten million, one hundred twenty-one thousand, two hundred seventeen".