21194140169 has 2 divisors, whose sum is σ = 21194140170. Its totient is φ = 21194140168.

The previous prime is 21194140141. The next prime is 21194140189. The reversal of 21194140169 is 96104149112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20366714944 + 827425225 = 142712^2 + 28765^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21194140169 is a prime.

It is a super-2 number, since 2×21194140169² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21194140189) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10597070084 + 10597070085.

It is an arithmetic number, because the mean of its divisors is an integer number (10597070085).

Almost surely, 2^21194140169 is an apocalyptic number.

It is an amenable number.

21194140169 is a deficient number, since it is larger than the sum of its proper divisors (1).

21194140169 is an equidigital number, since it uses as much as digits as its factorization.

21194140169 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 15552, while the sum is 38.

The spelling of 21194140169 in words is "twenty-one billion, one hundred ninety-four million, one hundred forty thousand, one hundred sixty-nine".