221728125 has 48 divisors (see below), whose sum is σ = 376100928. Its totient is φ = 116160000.

The previous prime is 221728121. The next prime is 221728153. The reversal of 221728125 is 521827122.

It is not a de Polignac number, because 221728125 - 2² = 221728121 is a prime.

It is a super-2 number, since 2×221728125² = 98326722832031250, which contains 22 as substring.

221728125 is a Rhonda number in base 10.

Its product of digits (4480) is a multiple of the sum of its prime factors (448).

It is a junction number, because it is equal to n+sod(n) for n = 221728092 and 221728101.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221728121) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 627949 + ... + 628301.

It is an arithmetic number, because the mean of its divisors is an integer number (7835436).

Almost surely, 2^221728125 is an apocalyptic number.

221728125 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

221728125 is a deficient number, since it is larger than the sum of its proper divisors (154372803).

221728125 is an frugal number, since it uses more digits than its factorization.

221728125 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 448 (or 428 counting only the distinct ones).

The product of its digits is 4480, while the sum is 30.

The square root of 221728125 is about 14890.5381031043. The cubic root of 221728125 is about 605.2576140341.

The spelling of 221728125 in words is "two hundred twenty-one million, seven hundred twenty-eight thousand, one hundred twenty-five".