21604842 has 24 divisors (see below), whose sum is σ = 53498016. Its totient is φ = 6172776.

The previous prime is 21604837. The next prime is 21604853. The reversal of 21604842 is 24840612.

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 11 ways as a sum of consecutive naturals, for example, 85608 + ... + 85859.

It is an arithmetic number, because the mean of its divisors is an integer number (2229084).

Almost surely, 2^21604842 is an apocalyptic number.

21604842 is an abundant number, since it is smaller than the sum of its proper divisors (31893174).

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

21604842 is a wasteful number, since it uses less digits than its factorization.

21604842 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 171482 (or 171479 counting only the distinct ones).

The product of its (nonzero) digits is 3072, while the sum is 27.

The square root of 21604842 is about 4648.1009025192. The cubic root of 21604842 is about 278.5161382519.

The spelling of 21604842 in words is "twenty-one million, six hundred four thousand, eight hundred forty-two".