261650401173125 has 10 divisors (see below), whose sum is σ = 326958341306718. Its totient is φ = 209320320938000.

The previous prime is 261650401173121. The next prime is 261650401173127. The reversal of 261650401173125 is 521371104056162.

It is a happy number.

It can be written as a sum of positive squares in 5 ways, for example, as 167048361228961 + 94602039944164 = 12924719^2 + 9726358^2 .

It is not a de Polignac number, because 261650401173125 - 2² = 261650401173121 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261650401173121) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 209320320314 + ... + 209320321563.

Almost surely, 2^{261650401173125} is an apocalyptic number.

261650401173125 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

261650401173125 is a deficient number, since it is larger than the sum of its proper divisors (65307940133593).

261650401173125 is an frugal number, since it uses more digits than its factorization.

261650401173125 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 418640641897 (or 418640641882 counting only the distinct ones).

The product of its (nonzero) digits is 302400, while the sum is 44.

The spelling of 261650401173125 in words is "two hundred sixty-one trillion, six hundred fifty billion, four hundred one million, one hundred seventy-three thousand, one hundred twenty-five".