21203089 has 4 divisors (see below), whose sum is σ = 21934260. Its totient is φ = 20471920.

The previous prime is 21203071. The next prime is 21203099. The reversal of 21203089 is 98030212.

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 5267025 + 15936064 = 2295^2 + 3992^2 .

It is a cyclic number.

It is not a de Polignac number, because 21203089 - 2¹¹ = 21201041 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21203099) 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, 365542 + ... + 365599.

It is an arithmetic number, because the mean of its divisors is an integer number (5483565).

Almost surely, 2^21203089 is an apocalyptic number.

21203089 is a gapful number since it is divisible by the number (29) formed by its first and last digit.

It is an amenable number.

21203089 is a deficient number, since it is larger than the sum of its proper divisors (731171).

21203089 is an equidigital number, since it uses as much as digits as its factorization.

21203089 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 731170.

The product of its (nonzero) digits is 864, while the sum is 25.

The square root of 21203089 is about 4604.6812050347. The cubic root of 21203089 is about 276.7789423501.

The spelling of 21203089 in words is "twenty-one million, two hundred three thousand, eighty-nine".