261779806125 has 256 divisors, whose sum is σ = 539179130880. Its totient is φ = 124720128000.

The previous prime is 261779806037. The next prime is 261779806139. The reversal of 261779806125 is 521608977162.

261779806125 is a `hidden beast` number, since 2 + 6 + 17 + 7 + 9 + 8 + 0 + 612 + 5 = 666.

It is not a de Polignac number, because 261779806125 - 2¹³ = 261779797933 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 255 ways as a sum of consecutive naturals, for example, 94265737 + ... + 94268513.

It is an arithmetic number, because the mean of its divisors is an integer number (2106168480).

Almost surely, 2^261779806125 is an apocalyptic number.

261779806125 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

261779806125 is an abundant number, since it is smaller than the sum of its proper divisors (277399324755).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

261779806125 is a wasteful number, since it uses less digits than its factorization.

261779806125 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2902 (or 2886 counting only the distinct ones).

The product of its (nonzero) digits is 2540160, while the sum is 54.

The spelling of 261779806125 in words is "two hundred sixty-one billion, seven hundred seventy-nine million, eight hundred six thousand, one hundred twenty-five".