21122200261 has 2 divisors, whose sum is σ = 21122200262. Its totient is φ = 21122200260.

The previous prime is 21122200223. The next prime is 21122200321. The reversal of 21122200261 is 16200222112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21045304900 + 76895361 = 145070^2 + 8769^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21122200261 is a prime.

It is a super-2 number, since 2×21122200261² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21122200361) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10561100130 + 10561100131.

It is an arithmetic number, because the mean of its divisors is an integer number (10561100131).

Almost surely, 2^21122200261 is an apocalyptic number.

It is an amenable number.

21122200261 is a deficient number, since it is larger than the sum of its proper divisors (1).

21122200261 is an equidigital number, since it uses as much as digits as its factorization.

21122200261 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 21122200261 its reverse (16200222112), we get a palindrome (37322422373).

The spelling of 21122200261 in words is "twenty-one billion, one hundred twenty-two million, two hundred thousand, two hundred sixty-one".