210121001 has 2 divisors, whose sum is σ = 210121002. Its totient is φ = 210121000.

The previous prime is 210120983. The next prime is 210121063. The reversal of 210121001 is 100121012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 187032976 + 23088025 = 13676^2 + 4805^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-210121001 is a prime.

It is a super-2 number, since 2×210121001² = 88301670122484002, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 210121001.

It is not a weakly prime, because it can be changed into another prime (210121801) 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, 105060500 + 105060501.

It is an arithmetic number, because the mean of its divisors is an integer number (105060501).

Almost surely, 2^210121001 is an apocalyptic number.

It is an amenable number.

210121001 is a deficient number, since it is larger than the sum of its proper divisors (1).

210121001 is an equidigital number, since it uses as much as digits as its factorization.

210121001 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4, while the sum is 8.

The square root of 210121001 is about 14495.5510761061. The cubic root of 210121001 is about 594.5063353410.

Adding to 210121001 its reverse (100121012), we get a palindrome (310242013).

It can be divided in two parts, 21012 and 1001, that multiplied together give a palindrome (21033012).

The spelling of 210121001 in words is "two hundred ten million, one hundred twenty-one thousand, one".