21888111121 has 2 divisors, whose sum is σ = 21888111122. Its totient is φ = 21888111120.

The previous prime is 21888111109. The next prime is 21888111149. The reversal of 21888111121 is 12111188812.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15304411521 + 6583699600 = 123711^2 + 81140^2 .

It is a cyclic number.

It is not a de Polignac number, because 21888111121 - 2¹⁵ = 21888078353 is a prime.

It is not a weakly prime, because it can be changed into another prime (21888111151) 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, 10944055560 + 10944055561.

It is an arithmetic number, because the mean of its divisors is an integer number (10944055561).

Almost surely, 2^21888111121 is an apocalyptic number.

It is an amenable number.

21888111121 is a deficient number, since it is larger than the sum of its proper divisors (1).

21888111121 is an equidigital number, since it uses as much as digits as its factorization.

21888111121 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2048, while the sum is 34.

Adding to 21888111121 its reverse (12111188812), we get a palindrome (33999299933).

The spelling of 21888111121 in words is "twenty-one billion, eight hundred eighty-eight million, one hundred eleven thousand, one hundred twenty-one".