21178304161 has 16 divisors (see below), whose sum is σ = 24821920000. Its totient is φ = 18061553664.

The previous prime is 21178304141. The next prime is 21178304167. The reversal of 21178304161 is 16140387112.

It is not a de Polignac number, because 21178304161 - 2¹³ = 21178295969 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21178304167) 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 in 15 ways as a sum of consecutive naturals, for example, 86880 + ... + 223393.

It is an arithmetic number, because the mean of its divisors is an integer number (1551370000).

Almost surely, 2^21178304161 is an apocalyptic number.

It is an amenable number.

21178304161 is a deficient number, since it is larger than the sum of its proper divisors (3643615839).

21178304161 is an equidigital number, since it uses as much as digits as its factorization.

21178304161 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 310493 (or 310479 counting only the distinct ones).

The product of its (nonzero) digits is 8064, while the sum is 34.

The spelling of 21178304161 in words is "twenty-one billion, one hundred seventy-eight million, three hundred four thousand, one hundred sixty-one".