261305125 has 8 divisors (see below), whose sum is σ = 326108952. Its totient is φ = 209044000.

The previous prime is 261305123. The next prime is 261305141. The reversal of 261305125 is 521503162.

It can be written as a sum of positive squares in 4 ways, for example, as 191844 + 261113281 = 438^2 + 16159^2 .

It is not a de Polignac number, because 261305125 - 2¹ = 261305123 is a prime.

It is a hoax number, since the sum of its digits (25) coincides with the sum of the digits of its distinct prime factors.

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

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 261305125.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261305123) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1045096 + ... + 1045345.

It is an arithmetic number, because the mean of its divisors is an integer number (40763619).

Almost surely, 2^261305125 is an apocalyptic number.

261305125 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

261305125 is a deficient number, since it is larger than the sum of its proper divisors (64803827).

261305125 is an equidigital number, since it uses as much as digits as its factorization.

261305125 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2090456 (or 2090446 counting only the distinct ones).

The product of its (nonzero) digits is 1800, while the sum is 25.

The square root of 261305125 is about 16164.9350447195. The cubic root of 261305125 is about 639.3165922775.

Adding to 261305125 its reverse (521503162), we get a palindrome (782808287).

The spelling of 261305125 in words is "two hundred sixty-one million, three hundred five thousand, one hundred twenty-five".