1666665900 has 54 divisors (see below), whose sum is σ = 5224074492. Its totient is φ = 444444000.

The previous prime is 1666665899. The next prime is 1666665953. The reversal of 1666665900 is 95666661.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 925026 + ... + 926825.

Almost surely, 2^1666665900 is an apocalyptic number.

1666665900 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1666665900 is an abundant number, since it is smaller than the sum of its proper divisors (3557408592).

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

1666665900 is a wasteful number, since it uses less digits than its factorization.

1666665900 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1851871 (or 1851861 counting only the distinct ones).

The product of its (nonzero) digits is 349920, while the sum is 45.

The square root of 1666665900 is about 40824.8196566745. The cubic root of 1666665900 is about 1185.6309196999.

The spelling of 1666665900 in words is "one billion, six hundred sixty-six million, six hundred sixty-five thousand, nine hundred".