21845872 has 10 divisors (see below), whose sum is σ = 42326408. Its totient is φ = 10922928.

The previous prime is 21845861. The next prime is 21845881. The reversal of 21845872 is 27854812.

It is a congruent number.

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 as a sum of consecutive naturals, namely, 682668 + ... + 682699.

Almost surely, 2^21845872 is an apocalyptic number.

It is an amenable number.

21845872 is a deficient number, since it is larger than the sum of its proper divisors (20480536).

21845872 is a wasteful number, since it uses less digits than its factorization.

21845872 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1365375 (or 1365369 counting only the distinct ones).

The product of its digits is 35840, while the sum is 37.

The square root of 21845872 is about 4673.9567819996. The cubic root of 21845872 is about 279.5480463953.

The spelling of 21845872 in words is "twenty-one million, eight hundred forty-five thousand, eight hundred seventy-two".