21789249 has 8 divisors (see below), whose sum is σ = 29989632. Its totient is φ = 14057520.

The previous prime is 21789241. The next prime is 21789281. The reversal of 21789249 is 94298712.

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

It is not a de Polignac number, because 21789249 - 2³ = 21789241 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21789249.

It is not an unprimeable number, because it can be changed into a prime (21789241) 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, 117054 + ... + 117239.

It is an arithmetic number, because the mean of its divisors is an integer number (3748704).

Almost surely, 2^21789249 is an apocalyptic number.

It is an amenable number.

21789249 is a deficient number, since it is larger than the sum of its proper divisors (8200383).

21789249 is a wasteful number, since it uses less digits than its factorization.

21789249 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 234327.

The product of its digits is 72576, while the sum is 42.

The square root of 21789249 is about 4667.8955643844. The cubic root of 21789249 is about 279.3063143110.

The spelling of 21789249 in words is "twenty-one million, seven hundred eighty-nine thousand, two hundred forty-nine".