210121801 has 2 divisors, whose sum is σ = 210121802. Its totient is φ = 210121800.

The previous prime is 210121789. The next prime is 210121811. The reversal of 210121801 is 108121012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 200505600 + 9616201 = 14160^2 + 3101^2 .

It is a cyclic number.

It is not a de Polignac number, because 210121801 - 2¹¹ = 210119753 is a prime.

It is not a weakly prime, because it can be changed into another prime (210121811) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 105060900 + 105060901.

It is an arithmetic number, because the mean of its divisors is an integer number (105060901).

Almost surely, 2^210121801 is an apocalyptic number.

It is an amenable number.

210121801 is a deficient number, since it is larger than the sum of its proper divisors (1).

210121801 is an equidigital number, since it uses as much as digits as its factorization.

210121801 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 32, while the sum is 16.

The square root of 210121801 is about 14495.5786707534. The cubic root of 210121801 is about 594.5070898339.

Adding to 210121801 its reverse (108121012), we get a palindrome (318242813).

The spelling of 210121801 in words is "two hundred ten million, one hundred twenty-one thousand, eight hundred one".