210221200261 has 2 divisors, whose sum is σ = 210221200262. Its totient is φ = 210221200260.

The previous prime is 210221200247. The next prime is 210221200327. The reversal of 210221200261 is 162002122012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 173414777761 + 36806422500 = 416431^2 + 191850^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-210221200261 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (210221260261) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 105110600130 + 105110600131.

It is an arithmetic number, because the mean of its divisors is an integer number (105110600131).

Almost surely, 2^210221200261 is an apocalyptic number.

It is an amenable number.

210221200261 is a deficient number, since it is larger than the sum of its proper divisors (1).

210221200261 is an equidigital number, since it uses as much as digits as its factorization.

210221200261 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 192, while the sum is 19.

Adding to 210221200261 its reverse (162002122012), we get a palindrome (372223322273).

The spelling of 210221200261 in words is "two hundred ten billion, two hundred twenty-one million, two hundred thousand, two hundred sixty-one".