21123221009977 has 2 divisors, whose sum is σ = 21123221009978. Its totient is φ = 21123221009976.

The previous prime is 21123221009911. The next prime is 21123221010029. The reversal of 21123221009977 is 77990012232112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16605062654761 + 4518158355216 = 4074931^2 + 2125596^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21123221009977 is a prime.

It is not a weakly prime, because it can be changed into another prime (21123221049977) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10561610504988 + 10561610504989.

It is an arithmetic number, because the mean of its divisors is an integer number (10561610504989).

Almost surely, 2^{21123221009977} is an apocalyptic number.

It is an amenable number.

21123221009977 is a deficient number, since it is larger than the sum of its proper divisors (1).

21123221009977 is an equidigital number, since it uses as much as digits as its factorization.

21123221009977 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 190512, while the sum is 46.

The spelling of 21123221009977 in words is "twenty-one trillion, one hundred twenty-three billion, two hundred twenty-one million, nine thousand, nine hundred seventy-seven".