25520332221 has 12 divisors (see below), whose sum is σ = 39031096572. Its totient is φ = 16012757376.

The previous prime is 25520332219. The next prime is 25520332297. The reversal of 25520332221 is 12223302552.

It can be written as a sum of positive squares in 2 ways, for example, as 21039502500 + 4480829721 = 145050^2 + 66939^2 .

It is not a de Polignac number, because 25520332221 - 2¹ = 25520332219 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (25520332121) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 83399626 + ... + 83399931.

It is an arithmetic number, because the mean of its divisors is an integer number (3252591381).

Almost surely, 2^25520332221 is an apocalyptic number.

It is an amenable number.

25520332221 is a deficient number, since it is larger than the sum of its proper divisors (13510764351).

25520332221 is a wasteful number, since it uses less digits than its factorization.

25520332221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 166799580 (or 166799577 counting only the distinct ones).

The product of its (nonzero) digits is 7200, while the sum is 27.

Adding to 25520332221 its reverse (12223302552), we get a palindrome (37743634773).

The spelling of 25520332221 in words is "twenty-five billion, five hundred twenty million, three hundred thirty-two thousand, two hundred twenty-one".