666154341661 has 6 divisors (see below), whose sum is σ = 688336381086. Its totient is φ = 644665491000.

The previous prime is 666154341623. The next prime is 666154341667. The reversal of 666154341661 is 166143451666.

666154341661 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 641168532900 + 24985808761 = 800730^2 + 158069^2 .

It is not a de Polignac number, because 666154341661 - 2³³ = 657564407069 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (666154341667) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 346593390 + ... + 346595311.

It is an arithmetic number, because the mean of its divisors is an integer number (114722730181).

Almost surely, 2^666154341661 is an apocalyptic number.

It is an amenable number.

666154341661 is a deficient number, since it is larger than the sum of its proper divisors (22182039425).

666154341661 is an equidigital number, since it uses as much as digits as its factorization.

666154341661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 693188763 (or 693188732 counting only the distinct ones).

The product of its digits is 1866240, while the sum is 49.

The spelling of 666154341661 in words is "six hundred sixty-six billion, one hundred fifty-four million, three hundred forty-one thousand, six hundred sixty-one".