21080803 has 4 divisors (see below), whose sum is σ = 21478608. Its totient is φ = 20683000.

The previous prime is 21080797. The next prime is 21080831. The reversal of 21080803 is 30808012.

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

It is a cyclic number.

It is not a de Polignac number, because 21080803 - 2⁵ = 21080771 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21080893) 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, 198823 + ... + 198928.

It is an arithmetic number, because the mean of its divisors is an integer number (5369652).

Almost surely, 2^21080803 is an apocalyptic number.

21080803 is a deficient number, since it is larger than the sum of its proper divisors (397805).

21080803 is an equidigital number, since it uses as much as digits as its factorization.

21080803 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 397804.

The product of its (nonzero) digits is 384, while the sum is 22.

The square root of 21080803 is about 4591.3835605403. The cubic root of 21080803 is about 276.2458208659.

Adding to 21080803 its reverse (30808012), we get a palindrome (51888815).

The spelling of 21080803 in words is "twenty-one million, eighty thousand, eight hundred three".