21728854 has 12 divisors (see below), whose sum is σ = 37914804. Its totient is φ = 9312324.

The previous prime is 21728851. The next prime is 21728857. The reversal of 21728854 is 45882712.

It is an interprime number because it is at equal distance from previous prime (21728851) and next prime (21728857).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21728851) 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 5 ways as a sum of consecutive naturals, for example, 110764 + ... + 110959.

It is an arithmetic number, because the mean of its divisors is an integer number (3159567).

Almost surely, 2^21728854 is an apocalyptic number.

21728854 is a deficient number, since it is larger than the sum of its proper divisors (16185950).

21728854 is a wasteful number, since it uses less digits than its factorization.

21728854 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 221739 (or 221732 counting only the distinct ones).

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

The square root of 21728854 is about 4661.4218860773. The cubic root of 21728854 is about 279.0480169837.

It can be divided in two parts, 2172 and 8854, that added together give a triangular number (11026 = T₁₄₈).

The spelling of 21728854 in words is "twenty-one million, seven hundred twenty-eight thousand, eight hundred fifty-four".