21161346161 has 2 divisors, whose sum is σ = 21161346162. Its totient is φ = 21161346160.

The previous prime is 21161346149. The next prime is 21161346191. The reversal of 21161346161 is 16164316112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 14409601600 + 6751744561 = 120040^2 + 82169^2 .

It is a cyclic number.

It is not a de Polignac number, because 21161346161 - 2²² = 21157151857 is a prime.

It is not a weakly prime, because it can be changed into another prime (21161346191) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10580673080 + 10580673081.

It is an arithmetic number, because the mean of its divisors is an integer number (10580673081).

Almost surely, 2^21161346161 is an apocalyptic number.

It is an amenable number.

21161346161 is a deficient number, since it is larger than the sum of its proper divisors (1).

21161346161 is an equidigital number, since it uses as much as digits as its factorization.

21161346161 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5184, while the sum is 32.

The spelling of 21161346161 in words is "twenty-one billion, one hundred sixty-one million, three hundred forty-six thousand, one hundred sixty-one".