2661605412138 has 24 divisors (see below), whose sum is σ = 5836291388928. Its totient is φ = 876512625192.

The previous prime is 2661605412121. The next prime is 2661605412157. The reversal of 2661605412138 is 8312145061662.

2661605412138 is a `hidden beast` number, since 2 + 6 + 6 + 1 + 605 + 4 + 1 + 2 + 1 + 38 = 666.

It is a junction number, because it is equal to n+sod(n) for n = 2661605412093 and 2661605412102.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 890763370 + ... + 890766357.

It is an arithmetic number, because the mean of its divisors is an integer number (243178807872).

Almost surely, 2^{2661605412138} is an apocalyptic number.

2661605412138 is an abundant number, since it is smaller than the sum of its proper divisors (3174685976790).

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

2661605412138 is a wasteful number, since it uses less digits than its factorization.

2661605412138 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1781529818 (or 1781529815 counting only the distinct ones).

The product of its (nonzero) digits is 414720, while the sum is 45.

The spelling of 2661605412138 in words is "two trillion, six hundred sixty-one billion, six hundred five million, four hundred twelve thousand, one hundred thirty-eight".