221445025 has 12 divisors (see below), whose sum is σ = 277313724. Its totient is φ = 175400000.

The previous prime is 221445013. The next prime is 221445047. The reversal of 221445025 is 520544122.

It can be written as a sum of positive squares in 6 ways, for example, as 42928704 + 178516321 = 6552^2 + 13361^2 .

It is not a de Polignac number, because 221445025 - 2¹³ = 221436833 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (25).

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 41326 + ... + 46375.

It is an arithmetic number, because the mean of its divisors is an integer number (23109477).

Almost surely, 2^221445025 is an apocalyptic number.

221445025 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

221445025 is a deficient number, since it is larger than the sum of its proper divisors (55868699).

221445025 is a wasteful number, since it uses less digits than its factorization.

221445025 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 87812 (or 87807 counting only the distinct ones).

The product of its (nonzero) digits is 3200, while the sum is 25.

The square root of 221445025 is about 14881.0290302788. The cubic root of 221445025 is about 604.9999089315. Note that the first 4 decimals are identical.

Adding to 221445025 its reverse (520544122), we get a palindrome (741989147).

The spelling of 221445025 in words is "two hundred twenty-one million, four hundred forty-five thousand, twenty-five".