21169689 has 4 divisors (see below), whose sum is σ = 28226256. Its totient is φ = 14113124.

The previous prime is 21169679. The next prime is 21169691. The reversal of 21169689 is 98696112.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21169689 - 2⁵ = 21169657 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21169689.

It is not an unprimeable number, because it can be changed into a prime (21169609) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3528279 + ... + 3528284.

It is an arithmetic number, because the mean of its divisors is an integer number (7056564).

Almost surely, 2^21169689 is an apocalyptic number.

It is an amenable number.

21169689 is a deficient number, since it is larger than the sum of its proper divisors (7056567).

21169689 is an equidigital number, since it uses as much as digits as its factorization.

21169689 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7056566.

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

The square root of 21169689 is about 4601.0530316440. The cubic root of 21169689 is about 276.6335346851.

The spelling of 21169689 in words is "twenty-one million, one hundred sixty-nine thousand, six hundred eighty-nine".