21803020 has 12 divisors (see below), whose sum is σ = 45786384. Its totient is φ = 8721200.

The previous prime is 21803003. The next prime is 21803039. The reversal of 21803020 is 2030812.

It is a happy number.

It is a super-2 number, since 2×21803020² = 950743362240800, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21802985 and 21803003.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 545056 + ... + 545095.

It is an arithmetic number, because the mean of its divisors is an integer number (3815532).

Almost surely, 2^21803020 is an apocalyptic number.

21803020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21803020 is an abundant number, since it is smaller than the sum of its proper divisors (23983364).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21803020 is a wasteful number, since it uses less digits than its factorization.

21803020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1090160 (or 1090158 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 16.

The square root of 21803020 is about 4669.3704072391. The cubic root of 21803020 is about 279.3651432811.

Adding to 21803020 its reverse (2030812), we get a palindrome (23833832).

The spelling of 21803020 in words is "twenty-one million, eight hundred three thousand, twenty".