21445418 has 8 divisors (see below), whose sum is σ = 32187780. Its totient is φ = 10716160.

The previous prime is 21445409. The next prime is 21445441. The reversal of 21445418 is 81454412.

It can be written as a sum of positive squares in 2 ways, for example, as 21279769 + 165649 = 4613^2 + 407^2 .

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

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 4778 + ... + 8106.

Almost surely, 2^21445418 is an apocalyptic number.

21445418 is a deficient number, since it is larger than the sum of its proper divisors (10742362).

21445418 is a wasteful number, since it uses less digits than its factorization.

21445418 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6552.

The product of its digits is 5120, while the sum is 29.

The square root of 21445418 is about 4630.9197790504. The cubic root of 21445418 is about 277.8293813580.

The spelling of 21445418 in words is "twenty-one million, four hundred forty-five thousand, four hundred eighteen".