1666666380 has 48 divisors (see below), whose sum is σ = 4707982944. Its totient is φ = 440509440.

The previous prime is 1666666373. The next prime is 1666666399. The reversal of 1666666380 is 836666661.

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 15 ways as a sum of consecutive naturals, for example, 116131 + ... + 129690.

It is an arithmetic number, because the mean of its divisors is an integer number (98082978).

Almost surely, 2^1666666380 is an apocalyptic number.

1666666380 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1666666380 is an abundant number, since it is smaller than the sum of its proper divisors (3041316564).

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

1666666380 is a wasteful number, since it uses less digits than its factorization.

1666666380 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 245946 (or 245944 counting only the distinct ones).

The product of its (nonzero) digits is 1119744, while the sum is 48.

The square root of 1666666380 is about 40824.8255354509. The cubic root of 1666666380 is about 1185.6310335205.

The spelling of 1666666380 in words is "one billion, six hundred sixty-six million, six hundred sixty-six thousand, three hundred eighty".