21601838 has 16 divisors (see below), whose sum is σ = 32931360. Its totient is φ = 10626336.

The previous prime is 21601831. The next prime is 21601843. The reversal of 21601838 is 83810612.

It is a self number, because there is not a number n which added to its sum of digits gives 21601838.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21601831) 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 7 ways as a sum of consecutive naturals, for example, 42695 + ... + 43197.

It is an arithmetic number, because the mean of its divisors is an integer number (2058210).

Almost surely, 2^21601838 is an apocalyptic number.

21601838 is a deficient number, since it is larger than the sum of its proper divisors (11329522).

21601838 is a wasteful number, since it uses less digits than its factorization.

21601838 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 811.

The product of its (nonzero) digits is 2304, while the sum is 29.

The square root of 21601838 is about 4647.7777485590. Note that the first 4 decimals coincide. The cubic root of 21601838 is about 278.5032290893.

The spelling of 21601838 in words is "twenty-one million, six hundred one thousand, eight hundred thirty-eight".