261651125 has 16 divisors (see below), whose sum is σ = 327440880. Its totient is φ = 208744000.

The previous prime is 261651119. The next prime is 261651133. The reversal of 261651125 is 521156162.

It is a happy number.

It can be written as a sum of positive squares in 8 ways, for example, as 143472484 + 118178641 = 11978^2 + 10871^2 .

It is not a de Polignac number, because 261651125 - 2¹⁶ = 261585589 is a prime.

It is a super-2 number, since 2×261651125² = 136922622427531250, which contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 45935 + ... + 51315.

It is an arithmetic number, because the mean of its divisors is an integer number (20465055).

Almost surely, 2^261651125 is an apocalyptic number.

261651125 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

261651125 is a deficient number, since it is larger than the sum of its proper divisors (65789755).

261651125 is an equidigital number, since it uses as much as digits as its factorization.

261651125 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5785 (or 5775 counting only the distinct ones).

The product of its digits is 3600, while the sum is 29.

The square root of 261651125 is about 16175.6336815594. The cubic root of 261651125 is about 639.5986456550.

The spelling of 261651125 in words is "two hundred sixty-one million, six hundred fifty-one thousand, one hundred twenty-five".