261666375146512 has 640 divisors, whose sum is σ = 625377173299200. Its totient is φ = 103719813120000.

The previous prime is 261666375146443. The next prime is 261666375146593. The reversal of 261666375146512 is 215641573666162.

It is a super-2 number, since 2×261666375146512² (a number of 30 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 659109257098 + ... + 659109257494.

It is an arithmetic number, because the mean of its divisors is an integer number (977151833280).

Almost surely, 2^{261666375146512} is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 261666375146512, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (312688586649600).

261666375146512 is an abundant number, since it is smaller than the sum of its proper divisors (363710798152688).

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

261666375146512 is a wasteful number, since it uses less digits than its factorization.

261666375146512 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1015 (or 1009 counting only the distinct ones).

The product of its digits is 65318400, while the sum is 61.

The spelling of 261666375146512 in words is "two hundred sixty-one trillion, six hundred sixty-six billion, three hundred seventy-five million, one hundred forty-six thousand, five hundred twelve".