261680855040 has 1920 divisors, whose sum is σ = 1130204275200. Its totient is φ = 57224724480.

The previous prime is 261680855021. The next prime is 261680855071. The reversal of 261680855040 is 40558086162.

261680855040 is a `hidden beast` number, since 2 + 6 + 1 + 68 + 0 + 85 + 504 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (1920).

It is a super-3 number, since 3×261680855040³ (a number of 35 digits) contains 333 as substring.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 159 ways as a sum of consecutive naturals, for example, 6085601259 + ... + 6085601301.

It is an arithmetic number, because the mean of its divisors is an integer number (588648060).

Almost surely, 2^261680855040 is an apocalyptic number.

261680855040 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 261680855040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (565102137600).

261680855040 is an abundant number, since it is smaller than the sum of its proper divisors (868523420160).

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

261680855040 is a wasteful number, since it uses less digits than its factorization.

261680855040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 145 (or 116 counting only the distinct ones).

The product of its (nonzero) digits is 460800, while the sum is 45.

The spelling of 261680855040 in words is "two hundred sixty-one billion, six hundred eighty million, eight hundred fifty-five thousand, forty".