21445210 has 32 divisors (see below), whose sum is σ = 40519440. Its totient is φ = 8160768.

The previous prime is 21445201. The next prime is 21445217. The reversal of 21445210 is 1254412.

It can be written as a sum of positive squares in 8 ways, for example, as 3101121 + 18344089 = 1761^2 + 4283^2 .

It is not an unprimeable number, because it can be changed into a prime (21445217) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 20664 + ... + 21676.

Almost surely, 2^21445210 is an apocalyptic number.

21445210 is a deficient number, since it is larger than the sum of its proper divisors (19074230).

21445210 is a wasteful number, since it uses less digits than its factorization.

21445210 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1122.

The product of its (nonzero) digits is 320, while the sum is 19.

The square root of 21445210 is about 4630.8973212543. The cubic root of 21445210 is about 277.8284831289.

Adding to 21445210 its reverse (1254412), we get a palindrome (22699622).

The spelling of 21445210 in words is "twenty-one million, four hundred forty-five thousand, two hundred ten".