2661345651666 has 32 divisors (see below), whose sum is σ = 5732191745280. Its totient is φ = 818866635264.

The previous prime is 2661345651641. The next prime is 2661345651691. The reversal of 2661345651666 is 6661565431662.

It is an interprime number because it is at equal distance from previous prime (2661345651641) and next prime (2661345651691).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 12455106 + ... + 12666978.

It is an arithmetic number, because the mean of its divisors is an integer number (179130992040).

Almost surely, 2^{2661345651666} is an apocalyptic number.

2661345651666 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

2661345651666 is an abundant number, since it is smaller than the sum of its proper divisors (3070846093614).

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

2661345651666 is a wasteful number, since it uses less digits than its factorization.

2661345651666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 372930.

The product of its digits is 27993600, while the sum is 57.

The spelling of 2661345651666 in words is "two trillion, six hundred sixty-one billion, three hundred forty-five million, six hundred fifty-one thousand, six hundred sixty-six".