21727838 has 16 divisors (see below), whose sum is σ = 36702720. Its totient is φ = 9557400.

The previous prime is 21727831. The next prime is 21727841. The reversal of 21727838 is 83872712.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21727831) 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, 15248 + ... + 16611.

It is an arithmetic number, because the mean of its divisors is an integer number (2293920).

Almost surely, 2^21727838 is an apocalyptic number.

21727838 is a deficient number, since it is larger than the sum of its proper divisors (14974882).

21727838 is a wasteful number, since it uses less digits than its factorization.

21727838 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31903.

The product of its digits is 37632, while the sum is 38.

The square root of 21727838 is about 4661.3129051803. The cubic root of 21727838 is about 279.0436676639.

The spelling of 21727838 in words is "twenty-one million, seven hundred twenty-seven thousand, eight hundred thirty-eight".