21805027 has 16 divisors (see below), whose sum is σ = 23680000. Its totient is φ = 20015424.

The previous prime is 21805019. The next prime is 21805037. The reversal of 21805027 is 72050812.

It is a cyclic number.

It is not a de Polignac number, because 21805027 - 2³ = 21805019 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21804992 and 21805010.

It is not an unprimeable number, because it can be changed into a prime (21805037) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 109474 + ... + 109672.

It is an arithmetic number, because the mean of its divisors is an integer number (1480000).

Almost surely, 2^21805027 is an apocalyptic number.

21805027 is a deficient number, since it is larger than the sum of its proper divisors (1874973).

21805027 is a wasteful number, since it uses less digits than its factorization.

21805027 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 370.

The product of its (nonzero) digits is 1120, while the sum is 25.

The square root of 21805027 is about 4669.5853134941. The cubic root of 21805027 is about 279.3737150086.

Adding to 21805027 its reverse (72050812), we get a palindrome (93855839).

The spelling of 21805027 in words is "twenty-one million, eight hundred five thousand, twenty-seven".