1661566565606 has 32 divisors (see below), whose sum is σ = 2744487036000. Its totient is φ = 751379473152.

The previous prime is 1661566565543. The next prime is 1661566565647. The reversal of 1661566565606 is 6065656651661.

It is a happy number.

It is a congruent number.

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, 8372561 + ... + 8568716.

It is an arithmetic number, because the mean of its divisors is an integer number (85765219875).

Almost surely, 2^{1661566565606} is an apocalyptic number.

1661566565606 is a deficient number, since it is larger than the sum of its proper divisors (1082920470394).

1661566565606 is a wasteful number, since it uses less digits than its factorization.

1661566565606 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16941416.

The product of its (nonzero) digits is 34992000, while the sum is 59.

The spelling of 1661566565606 in words is "one trillion, six hundred sixty-one billion, five hundred sixty-six million, five hundred sixty-five thousand, six hundred six".