21803871 has 8 divisors (see below), whose sum is σ = 29113264. Its totient is φ = 14515200.

The previous prime is 21803861. The next prime is 21803879. The reversal of 21803871 is 17830812.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21803871 - 2¹⁸ = 21541727 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 (21803879) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2530 + ... + 7071.

It is an arithmetic number, because the mean of its divisors is an integer number (3639158).

Almost surely, 2^21803871 is an apocalyptic number.

21803871 is a deficient number, since it is larger than the sum of its proper divisors (7309393).

21803871 is an equidigital number, since it uses as much as digits as its factorization.

21803871 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10361.

The product of its (nonzero) digits is 2688, while the sum is 30.

The square root of 21803871 is about 4669.4615321255. The cubic root of 21803871 is about 279.3687778944.

The spelling of 21803871 in words is "twenty-one million, eight hundred three thousand, eight hundred seventy-one".