2661813187840 has 144 divisors (see below), whose sum is σ = 6533460077760. Its totient is φ = 1038685306880.

The previous prime is 2661813187799. The next prime is 2661813187843. The reversal of 2661813187840 is 487813181662.

It is a hoax number, since the sum of its digits (55) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2661813187843) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9758592 + ... + 10027648.

It is an arithmetic number, because the mean of its divisors is an integer number (45371250540).

Almost surely, 2^{2661813187840} is an apocalyptic number.

2661813187840 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 2661813187840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3266730038880).

2661813187840 is an abundant number, since it is smaller than the sum of its proper divisors (3871646889920).

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

2661813187840 is a wasteful number, since it uses less digits than its factorization.

2661813187840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 269268 (or 269254 counting only the distinct ones).

The product of its (nonzero) digits is 3096576, while the sum is 55.

The spelling of 2661813187840 in words is "two trillion, six hundred sixty-one billion, eight hundred thirteen million, one hundred eighty-seven thousand, eight hundred forty".