221544369225 has 27 divisors (see below), whose sum is σ = 396823227463. Its totient is φ = 118153231440.

The previous prime is 221544369197. The next prime is 221544369251. The reversal of 221544369225 is 522963445122.

The square root of 221544369225 is 470685.

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

221544369225 is a `hidden beast` number, since 2 + 21 + 5 + 44 + 369 + 225 = 666.

It can be written as a sum of positive squares in only one way, i.e., 79755972921 + 141788396304 = 282411^2 + 376548^2 .

It is not a de Polignac number, because 221544369225 - 2⁷ = 221544369097 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 7044586 + ... + 7075964.

Almost surely, 2^221544369225 is an apocalyptic number.

221544369225 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

221544369225 is the 470685-th square number.

221544369225 is the 235343-rd centered octagonal number.

It is an amenable number.

221544369225 is a deficient number, since it is larger than the sum of its proper divisors (175278858238).

221544369225 is an frugal number, since it uses more digits than its factorization.

221544369225 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 62774 (or 31387 counting only the distinct ones).

The product of its digits is 1036800, while the sum is 45.

The spelling of 221544369225 in words is "two hundred twenty-one billion, five hundred forty-four million, three hundred sixty-nine thousand, two hundred twenty-five".