21775110121 has 2 divisors, whose sum is σ = 21775110122. Its totient is φ = 21775110120.

The previous prime is 21775110107. The next prime is 21775110131. The reversal of 21775110121 is 12101157712.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21305781225 + 469328896 = 145965^2 + 21664^2 .

It is a cyclic number.

It is not a de Polignac number, because 21775110121 - 2⁵ = 21775110089 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21775110121.

It is not a weakly prime, because it can be changed into another prime (21775110131) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10887555060 + 10887555061.

It is an arithmetic number, because the mean of its divisors is an integer number (10887555061).

Almost surely, 2^21775110121 is an apocalyptic number.

It is an amenable number.

21775110121 is a deficient number, since it is larger than the sum of its proper divisors (1).

21775110121 is an equidigital number, since it uses as much as digits as its factorization.

21775110121 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 980, while the sum is 28.

Adding to 21775110121 its reverse (12101157712), we get a palindrome (33876267833).

The spelling of 21775110121 in words is "twenty-one billion, seven hundred seventy-five million, one hundred ten thousand, one hundred twenty-one".