261852241225 has 27 divisors (see below), whose sum is σ = 331110195829. Its totient is φ = 205422869600.

The previous prime is 261852241201. The next prime is 261852241247. The reversal of 261852241225 is 522142258162.

It is a happy number.

The square root of 261852241225 is 511715.

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

It can be written as a sum of positive squares in 4 ways, for example, as 1972514569 + 259879726656 = 44413^2 + 509784^2 .

It is not a de Polignac number, because 261852241225 - 2⁵ = 261852241193 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 135603510 + ... + 135605440.

Almost surely, 2^261852241225 is an apocalyptic number.

261852241225 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

261852241225 is the 511715-th square number.

261852241225 is the 255858-th centered octagonal number.

It is an amenable number.

261852241225 is a deficient number, since it is larger than the sum of its proper divisors (69257954604).

261852241225 is an frugal number, since it uses more digits than its factorization.

261852241225 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3978 (or 1989 counting only the distinct ones).

The product of its digits is 153600, while the sum is 40.

Adding to 261852241225 its reverse (522142258162), we get a palindrome (783994499387).

The spelling of 261852241225 in words is "two hundred sixty-one billion, eight hundred fifty-two million, two hundred forty-one thousand, two hundred twenty-five".