261255630136020 has 72 divisors (see below), whose sum is σ = 792114703472736. Its totient is φ = 64309078184832.

The previous prime is 261255630136003. The next prime is 261255630136021. The reversal of 261255630136020 is 20631036552162.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261255630136021) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 12882417382 + ... + 12882437661.

It is an arithmetic number, because the mean of its divisors is an integer number (11001593103788).

Almost surely, 2^{261255630136020} is an apocalyptic number.

261255630136020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

261255630136020 is an abundant number, since it is smaller than the sum of its proper divisors (530859073336716).

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

261255630136020 is a wasteful number, since it uses less digits than its factorization.

261255630136020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25764855081 (or 25764855066 counting only the distinct ones).

The product of its (nonzero) digits is 388800, while the sum is 42.

Adding to 261255630136020 its reverse (20631036552162), we get a palindrome (281886666688182).

The spelling of 261255630136020 in words is "two hundred sixty-one trillion, two hundred fifty-five billion, six hundred thirty million, one hundred thirty-six thousand, twenty".