21845418 has 16 divisors (see below), whose sum is σ = 49932480. Its totient is φ = 6241536.

The previous prime is 21845401. The next prime is 21845431. The reversal of 21845418 is 81454812.

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 7 ways as a sum of consecutive naturals, for example, 260023 + ... + 260106.

It is an arithmetic number, because the mean of its divisors is an integer number (3120780).

Almost surely, 2^21845418 is an apocalyptic number.

21845418 is an abundant number, since it is smaller than the sum of its proper divisors (28087062).

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

21845418 is a wasteful number, since it uses less digits than its factorization.

21845418 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 520141.

The product of its digits is 10240, while the sum is 33.

The square root of 21845418 is about 4673.9082147599. The cubic root of 21845418 is about 279.5461098633.

The spelling of 21845418 in words is "twenty-one million, eight hundred forty-five thousand, four hundred eighteen".