1666541664 has 36 divisors (see below), whose sum is σ = 4739228676. Its totient is φ = 555513792.

The previous prime is 1666541633. The next prime is 1666541677. The reversal of 1666541664 is 4661456661.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (36).

It is a super-2 number, since 2×1666541664² = 5554722235695777792, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 2893014 + ... + 2893589.

It is an arithmetic number, because the mean of its divisors is an integer number (131645241).

Almost surely, 2^1666541664 is an apocalyptic number.

It is an amenable number.

1666541664 is an abundant number, since it is smaller than the sum of its proper divisors (3072687012).

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

1666541664 is a wasteful number, since it uses less digits than its factorization.

1666541664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5786619 (or 5786608 counting only the distinct ones).

The product of its digits is 622080, while the sum is 45.

The square root of 1666541664 is about 40823.2980539299. The cubic root of 1666541664 is about 1185.6014593457.

The spelling of 1666541664 in words is "one billion, six hundred sixty-six million, five hundred forty-one thousand, six hundred sixty-four".