21669169 has 8 divisors (see below), whose sum is σ = 23021928. Its totient is φ = 20325120.

The previous prime is 21669157. The next prime is 21669173. The reversal of 21669169 is 96196612.

It can be written as a sum of positive squares in 4 ways, for example, as 144 + 21669025 = 12^2 + 4655^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21669169 - 2¹⁵ = 21636401 is a prime.

It is a super-2 number, since 2×21669169² = 939105770301122, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21669149) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3379 + ... + 7399.

It is an arithmetic number, because the mean of its divisors is an integer number (2877741).

Almost surely, 2^21669169 is an apocalyptic number.

It is an amenable number.

21669169 is a deficient number, since it is larger than the sum of its proper divisors (1352759).

21669169 is a wasteful number, since it uses less digits than its factorization.

21669169 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4355.

The product of its digits is 34992, while the sum is 40.

The square root of 21669169 is about 4655.0154672138. The cubic root of 21669169 is about 278.7922855408.

The spelling of 21669169 in words is "twenty-one million, six hundred sixty-nine thousand, one hundred sixty-nine".