21968169 has 8 divisors (see below), whose sum is σ = 30005472. Its totient is φ = 14288160.

The previous prime is 21968159. The next prime is 21968171. The reversal of 21968169 is 96186912.

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

It is not a de Polignac number, because 21968169 - 2⁴ = 21968153 is a prime.

It is a super-3 number, since 3×21968169³ (a number of 23 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 21968169.

It is not an unprimeable number, because it can be changed into a prime (21968159) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 89179 + ... + 89424.

It is an arithmetic number, because the mean of its divisors is an integer number (3750684).

Almost surely, 2^21968169 is an apocalyptic number.

It is an amenable number.

21968169 is a deficient number, since it is larger than the sum of its proper divisors (8037303).

21968169 is a wasteful number, since it uses less digits than its factorization.

21968169 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 178647.

The product of its digits is 46656, while the sum is 42.

The square root of 21968169 is about 4687.0213355606. The cubic root of 21968169 is about 280.0687288767.

The spelling of 21968169 in words is "twenty-one million, nine hundred sixty-eight thousand, one hundred sixty-nine".