1664742666 has 8 divisors (see below), whose sum is σ = 3329485344. Its totient is φ = 554914220.

The previous prime is 1664742647. The next prime is 1664742671. The reversal of 1664742666 is 6662474661.

1664742666 is digitally balanced in base 4, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

1664742666 is an admirable number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 138728550 + ... + 138728561.

It is an arithmetic number, because the mean of its divisors is an integer number (416185668).

Almost surely, 2^1664742666 is an apocalyptic number.

1664742666 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

1664742666 is a wasteful number, since it uses less digits than its factorization.

1664742666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 277457116.

The product of its digits is 1741824, while the sum is 48.

The square root of 1664742666 is about 40801.2581423661. The cubic root of 1664742666 is about 1185.1746948203.

The spelling of 1664742666 in words is "one billion, six hundred sixty-four million, seven hundred forty-two thousand, six hundred sixty-six".