225728561881 has 3 divisors (see below), whose sum is σ = 225729036991. Its totient is φ = 225728086772.

The previous prime is 225728561809. The next prime is 225728561887. The reversal of 225728561881 is 188165827522.

The square root of 225728561881 is 475109.

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

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in only one way, i.e., 14146961481 + 211581600400 = 118941^2 + 459980^2 .

It is not a de Polignac number, because 225728561881 - 2¹⁹ = 225728037593 is a prime.

It is a super-2 number, since 2×225728561881² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (225728561887) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 237555 + ... + 712663.

Almost surely, 2^225728561881 is an apocalyptic number.

225728561881 is the 475109-th square number.

225728561881 is the 237555-th centered octagonal number.

It is an amenable number.

225728561881 is a deficient number, since it is larger than the sum of its proper divisors (475110).

225728561881 is an frugal number, since it uses more digits than its factorization.

225728561881 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 950218 (or 475109 counting only the distinct ones).

The product of its digits is 4300800, while the sum is 55.

The spelling of 225728561881 in words is "two hundred twenty-five billion, seven hundred twenty-eight million, five hundred sixty-one thousand, eight hundred eighty-one".