2661905857680 has 400 divisors, whose sum is σ = 9285291417600. Its totient is φ = 706771215360.

The previous prime is 2661905857651. The next prime is 2661905857733. The reversal of 2661905857680 is 867585091662.

2661905857680 is a `hidden beast` number, since 2 + 6 + 6 + 1 + 9 + 0 + 58 + 576 + 8 + 0 = 666.

It is an unprimeable number.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 2081239281 + ... + 2081240559.

It is an arithmetic number, because the mean of its divisors is an integer number (23213228544).

Almost surely, 2^{2661905857680} is an apocalyptic number.

2661905857680 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 2661905857680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (4642645708800).

2661905857680 is an abundant number, since it is smaller than the sum of its proper divisors (6623385559920).

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

2661905857680 is a wasteful number, since it uses less digits than its factorization.

2661905857680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2444 (or 2429 counting only the distinct ones).

The product of its (nonzero) digits is 43545600, while the sum is 63.

The spelling of 2661905857680 in words is "two trillion, six hundred sixty-one billion, nine hundred five million, eight hundred fifty-seven thousand, six hundred eighty".