261636341760 has 960 divisors, whose sum is σ = 1004085734400. Its totient is φ = 64465403904.

The previous prime is 261636341719. The next prime is 261636341761. The reversal of 261636341760 is 67143636162.

261636341760 is a `hidden beast` number, since 2 + 6 + 1 + 6 + 3 + 634 + 1 + 7 + 6 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (960).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261636341761) by changing a digit.

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 63 ways as a sum of consecutive naturals, for example, 1882275771 + ... + 1882275909.

It is an arithmetic number, because the mean of its divisors is an integer number (1045922640).

Almost surely, 2^261636341760 is an apocalyptic number.

261636341760 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 261636341760, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (502042867200).

261636341760 is an abundant number, since it is smaller than the sum of its proper divisors (742449392640).

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

261636341760 is a wasteful number, since it uses less digits than its factorization.

261636341760 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 241 (or 209 counting only the distinct ones).

The product of its (nonzero) digits is 653184, while the sum is 45.

The spelling of 261636341760 in words is "two hundred sixty-one billion, six hundred thirty-six million, three hundred forty-one thousand, seven hundred sixty".