21122605 has 8 divisors (see below), whose sum is σ = 28968192. Its totient is φ = 14484048.

The previous prime is 21122603. The next prime is 21122611. The reversal of 21122605 is 50622112.

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

It is a cyclic number.

It is not a de Polignac number, because 21122605 - 2¹ = 21122603 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 (21122603) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 301717 + ... + 301786.

It is an arithmetic number, because the mean of its divisors is an integer number (3621024).

Almost surely, 2^21122605 is an apocalyptic number.

It is an amenable number.

21122605 is a deficient number, since it is larger than the sum of its proper divisors (7845587).

21122605 is an equidigital number, since it uses as much as digits as its factorization.

21122605 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 603515.

The product of its (nonzero) digits is 240, while the sum is 19.

The square root of 21122605 is about 4595.9335286751. The cubic root of 21122605 is about 276.4282934128.

Adding to 21122605 its reverse (50622112), we get a palindrome (71744717).

The spelling of 21122605 in words is "twenty-one million, one hundred twenty-two thousand, six hundred five".