21066919169 has 16 divisors (see below), whose sum is σ = 21368288592. Its totient is φ = 20767961088.

The previous prime is 21066919121. The next prime is 21066919219. The reversal of 21066919169 is 96191966012.

It can be written as a sum of positive squares in 8 ways, for example, as 15952953025 + 5113966144 = 126305^2 + 71512^2 .

It is a cyclic number.

It is not a de Polignac number, because 21066919169 - 2¹² = 21066915073 is a prime.

It is a super-2 number, since 2×21066919169² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21066909169) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 27253067 + ... + 27253839.

It is an arithmetic number, because the mean of its divisors is an integer number (1335518037).

Almost surely, 2^21066919169 is an apocalyptic number.

It is an amenable number.

21066919169 is a deficient number, since it is larger than the sum of its proper divisors (301369423).

21066919169 is a wasteful number, since it uses less digits than its factorization.

21066919169 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1876.

The product of its (nonzero) digits is 314928, while the sum is 50.

The spelling of 21066919169 in words is "twenty-one billion, sixty-six million, nine hundred nineteen thousand, one hundred sixty-nine".