21222722177 has 2 divisors, whose sum is σ = 21222722178. Its totient is φ = 21222722176.

The previous prime is 21222722167. The next prime is 21222722237. The reversal of 21222722177 is 77122722212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20782393921 + 440328256 = 144161^2 + 20984^2 .

It is a cyclic number.

It is not a de Polignac number, because 21222722177 - 2⁴ = 21222722161 is a prime.

It is not a weakly prime, because it can be changed into another prime (21222722117) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10611361088 + 10611361089.

It is an arithmetic number, because the mean of its divisors is an integer number (10611361089).

Almost surely, 2^21222722177 is an apocalyptic number.

It is an amenable number.

21222722177 is a deficient number, since it is larger than the sum of its proper divisors (1).

21222722177 is an equidigital number, since it uses as much as digits as its factorization.

21222722177 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 21952, while the sum is 35.

Adding to 21222722177 its sum of digits (35), we get a palindrome (21222722212).

The spelling of 21222722177 in words is "twenty-one billion, two hundred twenty-two million, seven hundred twenty-two thousand, one hundred seventy-seven".