2561810033646 has 144 divisors (see below), whose sum is σ = 6137737233264. Its totient is φ = 800647193088.

The previous prime is 2561810033641. The next prime is 2561810033647. The reversal of 2561810033646 is 6463300181652.

2561810033646 is a `hidden beast` number, since 2 + 561 + 8 + 10 + 0 + 3 + 36 + 46 = 666.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2561810033641) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 16942996 + ... + 17093528.

It is an arithmetic number, because the mean of its divisors is an integer number (42623175231).

Almost surely, 2^{2561810033646} is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 2561810033646, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3068868616632).

2561810033646 is an abundant number, since it is smaller than the sum of its proper divisors (3575927199618).

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

2561810033646 is a wasteful number, since it uses less digits than its factorization.

2561810033646 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 150685 (or 150654 counting only the distinct ones).

The product of its (nonzero) digits is 622080, while the sum is 45.

The spelling of 2561810033646 in words is "two trillion, five hundred sixty-one billion, eight hundred ten million, thirty-three thousand, six hundred forty-six".