21409189 has 8 divisors (see below), whose sum is σ = 22159872. Its totient is φ = 20662320.

The previous prime is 21409187. The next prime is 21409207. The reversal of 21409189 is 98190412.

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 21409189 - 2¹ = 21409187 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21409183) 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, 14907 + ... + 16279.

It is an arithmetic number, because the mean of its divisors is an integer number (2769984).

Almost surely, 2^21409189 is an apocalyptic number.

It is an amenable number.

21409189 is a deficient number, since it is larger than the sum of its proper divisors (750683).

21409189 is a wasteful number, since it uses less digits than its factorization.

21409189 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1907.

The product of its (nonzero) digits is 5184, while the sum is 34.

The square root of 21409189 is about 4627.0064836782. The cubic root of 21409189 is about 277.6728420287.

The spelling of 21409189 in words is "twenty-one million, four hundred nine thousand, one hundred eighty-nine".