21456489 has 8 divisors (see below), whose sum is σ = 29306592. Its totient is φ = 13955360.

The previous prime is 21456481. The next prime is 21456503. The reversal of 21456489 is 98465412.

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 21456489 - 2³ = 21456481 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21456481) 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, 87099 + ... + 87344.

It is an arithmetic number, because the mean of its divisors is an integer number (3663324).

Almost surely, 2^21456489 is an apocalyptic number.

It is an amenable number.

21456489 is a deficient number, since it is larger than the sum of its proper divisors (7850103).

21456489 is a wasteful number, since it uses less digits than its factorization.

21456489 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 174487.

The product of its digits is 69120, while the sum is 39.

The square root of 21456489 is about 4632.1149597133. The cubic root of 21456489 is about 277.8771820886.

It can be divided in two parts, 21456 and 489, that added together give a triangular number (21945 = T₂₀₉).

The spelling of 21456489 in words is "twenty-one million, four hundred fifty-six thousand, four hundred eighty-nine".