21456385 has 8 divisors (see below), whose sum is σ = 25779240. Its totient is φ = 17144064.

The previous prime is 21456373. The next prime is 21456403. The reversal of 21456385 is 58365412.

It can be written as a sum of positive squares in 4 ways, for example, as 961 + 21455424 = 31^2 + 4632^2 .

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 21456385 - 2⁷ = 21456257 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a plaindrome in base 11.

It is a self number, because there is not a number n which added to its sum of digits gives 21456385.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2919 + ... + 7171.

It is an arithmetic number, because the mean of its divisors is an integer number (3222405).

Almost surely, 2^21456385 is an apocalyptic number.

It is an amenable number.

21456385 is a deficient number, since it is larger than the sum of its proper divisors (4322855).

21456385 is a wasteful number, since it uses less digits than its factorization.

21456385 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5267.

The product of its digits is 28800, while the sum is 34.

The square root of 21456385 is about 4632.1037337262. The cubic root of 21456385 is about 277.8767331292.

The spelling of 21456385 in words is "twenty-one million, four hundred fifty-six thousand, three hundred eighty-five".