21485389 has 4 divisors (see below), whose sum is σ = 21609756. Its totient is φ = 21361024.

The previous prime is 21485357. The next prime is 21485413. The reversal of 21485389 is 98358412.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 20629764 + 855625 = 4542^2 + 925^2 .

It is a cyclic number.

It is not a de Polignac number, because 21485389 - 2⁵ = 21485357 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 (21485329) 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, 61924 + ... + 62269.

It is an arithmetic number, because the mean of its divisors is an integer number (5402439).

Almost surely, 2^21485389 is an apocalyptic number.

It is an amenable number.

21485389 is a deficient number, since it is larger than the sum of its proper divisors (124367).

21485389 is a wasteful number, since it uses less digits than its factorization.

21485389 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 124366.

The product of its digits is 69120, while the sum is 40.

The square root of 21485389 is about 4635.2334353299. The cubic root of 21485389 is about 278.0018848103.

The spelling of 21485389 in words is "twenty-one million, four hundred eighty-five thousand, three hundred eighty-nine".