2505173221 has 4 divisors (see below), whose sum is σ = 2505812512. Its totient is φ = 2504533932.

The previous prime is 2505173219. The next prime is 2505173257. The reversal of 2505173221 is 1223715052.

2505173221 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 2505173221 - 2¹ = 2505173219 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 2505173221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2505173621) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 313731 + ... + 321616.

It is an arithmetic number, because the mean of its divisors is an integer number (626453128).

Almost surely, 2^2505173221 is an apocalyptic number.

It is an amenable number.

2505173221 is a deficient number, since it is larger than the sum of its proper divisors (639291).

2505173221 is an equidigital number, since it uses as much as digits as its factorization.

2505173221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 639290.

The product of its (nonzero) digits is 4200, while the sum is 28.

The square root of 2505173221 is about 50051.7054754381. The cubic root of 2505173221 is about 1358.1443154636.

Adding to 2505173221 its reverse (1223715052), we get a palindrome (3728888273).

The spelling of 2505173221 in words is "two billion, five hundred five million, one hundred seventy-three thousand, two hundred twenty-one".