1666351188 has 18 divisors (see below), whose sum is σ = 4212165594. Its totient is φ = 555450384.

The previous prime is 1666351177. The next prime is 1666351241. The reversal of 1666351188 is 8811536661.

It can be written as a sum of positive squares in only one way, i.e., 1666109124 + 242064 = 40818^2 + 492^2 .

It is a tau number, because it is divible by the number of its divisors (18).

It is a super-2 number, since 2×1666351188² = 5553452563498022688, 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 (11) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 23143731 + ... + 23143802.

Almost surely, 2^1666351188 is an apocalyptic number.

1666351188 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is an amenable number.

1666351188 is an abundant number, since it is smaller than the sum of its proper divisors (2545814406).

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

1666351188 is a wasteful number, since it uses less digits than its factorization.

1666351188 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 46287543 (or 46287538 counting only the distinct ones).

The product of its digits is 207360, while the sum is 45.

The square root of 1666351188 is about 40820.9650547363. The cubic root of 1666351188 is about 1185.5562885123.

The spelling of 1666351188 in words is "one billion, six hundred sixty-six million, three hundred fifty-one thousand, one hundred eighty-eight".