656128225 has 27 divisors (see below), whose sum is σ = 838974297. Its totient is φ = 509021280.

The previous prime is 656128223. The next prime is 656128267. The reversal of 656128225 is 522821656.

The square root of 656128225 is 25615.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 4 ways, for example, as 2405601 + 653722624 = 1551^2 + 25568^2 .

It is not a de Polignac number, because 656128225 - 2¹ = 656128223 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (656128223) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 6019471 + ... + 6019579.

Almost surely, 2^656128225 is an apocalyptic number.

656128225 is the 25615-th square number.

656128225 is the 12808-th centered octagonal number.

It is an amenable number.

656128225 is a deficient number, since it is larger than the sum of its proper divisors (182846072).

656128225 is an equidigital number, since it uses as much as digits as its factorization.

656128225 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 322 (or 161 counting only the distinct ones).

The product of its digits is 57600, while the sum is 37.

The cubic root of 656128225 is about 868.9529063861.

Multiplying 656128225 by its product of digits (57600), we get a square (37792985760000 = 6147600²).

It can be divided in two parts, 65612 and 8225, that added together give a palindrome (73837).

The spelling of 656128225 in words is "six hundred fifty-six million, one hundred twenty-eight thousand, two hundred twenty-five".