21805107 has 8 divisors (see below), whose sum is σ = 29269200. Its totient is φ = 14438880.

The previous prime is 21805079. The next prime is 21805117. The reversal of 21805107 is 70150812.

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

It is not a de Polignac number, because 21805107 - 2¹¹ = 21803059 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21805117) 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, 23944 + ... + 24837.

It is an arithmetic number, because the mean of its divisors is an integer number (3658650).

Almost surely, 2^21805107 is an apocalyptic number.

21805107 is a deficient number, since it is larger than the sum of its proper divisors (7464093).

21805107 is a wasteful number, since it uses less digits than its factorization.

21805107 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 48933.

The product of its (nonzero) digits is 560, while the sum is 24.

The square root of 21805107 is about 4669.5938795574. The cubic root of 21805107 is about 279.3740566709.

Adding to 21805107 its reverse (70150812), we get a palindrome (91955919).

It can be divided in two parts, 21805 and 107, that added together give a palindrome (21912).

The spelling of 21805107 in words is "twenty-one million, eight hundred five thousand, one hundred seven".