21210202220117 has 2 divisors, whose sum is σ = 21210202220118. Its totient is φ = 21210202220116.

The previous prime is 21210202220099. The next prime is 21210202220131. The reversal of 21210202220117 is 71102220201212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16796341575556 + 4413860644561 = 4098334^2 + 2100919^2 .

It is a cyclic number.

It is not a de Polignac number, because 21210202220117 - 2²² = 21210198025813 is a prime.

It is a super-2 number, since 2×21210202220117² (a number of 27 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21210202220092 and 21210202220101.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21210202220177) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10605101110058 + 10605101110059.

It is an arithmetic number, because the mean of its divisors is an integer number (10605101110059).

Almost surely, 2^{21210202220117} is an apocalyptic number.

It is an amenable number.

21210202220117 is a deficient number, since it is larger than the sum of its proper divisors (1).

21210202220117 is an equidigital number, since it uses as much as digits as its factorization.

21210202220117 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 448, while the sum is 23.

Adding to 21210202220117 its reverse (71102220201212), we get a palindrome (92312422421329).

The spelling of 21210202220117 in words is "twenty-one trillion, two hundred ten billion, two hundred two million, two hundred twenty thousand, one hundred seventeen".