21201200261 has 2 divisors, whose sum is σ = 21201200262. Its totient is φ = 21201200260.

The previous prime is 21201200231. The next prime is 21201200303. The reversal of 21201200261 is 16200210212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21201107236 + 93025 = 145606^2 + 305^2 .

It is a cyclic number.

It is not a de Polignac number, because 21201200261 - 2¹⁰ = 21201199237 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21201200221) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10600600130 + 10600600131.

It is an arithmetic number, because the mean of its divisors is an integer number (10600600131).

Almost surely, 2^21201200261 is an apocalyptic number.

It is an amenable number.

21201200261 is a deficient number, since it is larger than the sum of its proper divisors (1).

21201200261 is an equidigital number, since it uses as much as digits as its factorization.

21201200261 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 96, while the sum is 17.

Adding to 21201200261 its reverse (16200210212), we get a palindrome (37401410473).

The spelling of 21201200261 in words is "twenty-one billion, two hundred one million, two hundred thousand, two hundred sixty-one".