211645728 has 144 divisors (see below), whose sum is σ = 692153280. Its totient is φ = 60092928.

The previous prime is 211645691. The next prime is 211645751. The reversal of 211645728 is 827546112.

211645728 is a `hidden beast` number, since 2 + 1 + 1 + 645 + 7 + 2 + 8 = 666.

It is a tau number, because it is divible by the number of its divisors (144).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 211645692 and 211645701.

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 in 23 ways as a sum of consecutive naturals, for example, 558243 + ... + 558621.

It is an arithmetic number, because the mean of its divisors is an integer number (4806620).

Almost surely, 2^211645728 is an apocalyptic number.

211645728 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 211645728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (346076640).

211645728 is an abundant number, since it is smaller than the sum of its proper divisors (480507552).

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

211645728 is a wasteful number, since it uses less digits than its factorization.

211645728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 679 (or 668 counting only the distinct ones).

The product of its digits is 26880, while the sum is 36.

The square root of 211645728 is about 14548.0489413529. The cubic root of 211645728 is about 595.9408676676.

The spelling of 211645728 in words is "two hundred eleven million, six hundred forty-five thousand, seven hundred twenty-eight".