221168728 has 16 divisors (see below), whose sum is σ = 452390760. Its totient is φ = 100531200.

The previous prime is 221168693. The next prime is 221168747. The reversal of 221168728 is 827861122.

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 3 ways as a sum of consecutive naturals, for example, 1256553 + ... + 1256728.

Almost surely, 2^221168728 is an apocalyptic number.

It is an amenable number.

221168728 is an abundant number, since it is smaller than the sum of its proper divisors (231222032).

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

221168728 is a wasteful number, since it uses less digits than its factorization.

221168728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2513298 (or 2513294 counting only the distinct ones).

The product of its digits is 21504, while the sum is 37.

The square root of 221168728 is about 14871.7426013228. The cubic root of 221168728 is about 604.7481847097.

The spelling of 221168728 in words is "two hundred twenty-one million, one hundred sixty-eight thousand, seven hundred twenty-eight".