261738509835600 has 1680 divisors, whose sum is σ = 1140584075030400. Its totient is φ = 56419107655680.

The previous prime is 261738509835599. The next prime is 261738509835631. The reversal of 261738509835600 is 6538905837162.

261738509835600 is a `hidden beast` number, since 2 + 6 + 1 + 7 + 38 + 509 + 8 + 35 + 60 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (1680).

It is a Harshad number since it is a multiple of its sum of digits (63).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 335 ways as a sum of consecutive naturals, for example, 2545324986 + ... + 2545427814.

It is an arithmetic number, because the mean of its divisors is an integer number (678919092280).

Almost surely, 2^{261738509835600} is an apocalyptic number.

261738509835600 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 261738509835600, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (570292037515200).

261738509835600 is an abundant number, since it is smaller than the sum of its proper divisors (878845565194800).

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

261738509835600 is a wasteful number, since it uses less digits than its factorization.

261738509835600 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 102944 (or 102918 counting only the distinct ones).

The product of its (nonzero) digits is 65318400, while the sum is 63.

The spelling of 261738509835600 in words is "two hundred sixty-one trillion, seven hundred thirty-eight billion, five hundred nine million, eight hundred thirty-five thousand, six hundred".