21214305 has 60 divisors (see below), whose sum is σ = 44278740. Its totient is φ = 9688896.

The previous prime is 21214273. The next prime is 21214309. The reversal of 21214305 is 50341212.

It can be written as a sum of positive squares in 2 ways, for example, as 8767521 + 12446784 = 2961^2 + 3528^2 .

It is not a de Polignac number, because 21214305 - 2⁵ = 21214273 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is not an unprimeable number, because it can be changed into a prime (21214309) 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 59 ways as a sum of consecutive naturals, for example, 19311 + ... + 20379.

It is an arithmetic number, because the mean of its divisors is an integer number (737979).

Almost surely, 2^21214305 is an apocalyptic number.

It is an amenable number.

21214305 is an abundant number, since it is smaller than the sum of its proper divisors (23064435).

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

21214305 is a wasteful number, since it uses less digits than its factorization.

21214305 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1100 (or 1084 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 18.

The square root of 21214305 is about 4605.8989350614. The cubic root of 21214305 is about 276.8277372120.

Adding to 21214305 its reverse (50341212), we get a palindrome (71555517).

The spelling of 21214305 in words is "twenty-one million, two hundred fourteen thousand, three hundred five".