21161347169 has 2 divisors, whose sum is σ = 21161347170. Its totient is φ = 21161347168.

The previous prime is 21161347157. The next prime is 21161347177. The reversal of 21161347169 is 96174316112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17026857169 + 4134490000 = 130487^2 + 64300^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21161347169 is a prime.

It is a super-2 number, since 2×21161347169² (a number of 21 digits) contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (21161347369) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10580673584 + 10580673585.

It is an arithmetic number, because the mean of its divisors is an integer number (10580673585).

Almost surely, 2^21161347169 is an apocalyptic number.

It is an amenable number.

21161347169 is a deficient number, since it is larger than the sum of its proper divisors (1).

21161347169 is an equidigital number, since it uses as much as digits as its factorization.

21161347169 is an evil number, because the sum of its binary digits is even.

The product of its digits is 54432, while the sum is 41.

The spelling of 21161347169 in words is "twenty-one billion, one hundred sixty-one million, three hundred forty-seven thousand, one hundred sixty-nine".