1666707840 has 384 divisors, whose sum is σ = 6825611520. Its totient is φ = 380712960.

The previous prime is 1666707827. The next prime is 1666707859. The reversal of 1666707840 is 487076661.

It is a tau number, because it is divible by the number of its divisors (384).

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1087875 + ... + 1089405.

It is an arithmetic number, because the mean of its divisors is an integer number (17775030).

Almost surely, 2^1666707840 is an apocalyptic number.

1666707840 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1666707840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3412805760).

1666707840 is an abundant number, since it is smaller than the sum of its proper divisors (5158903680).

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

1666707840 is an equidigital number, since it uses as much as digits as its factorization.

1666707840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1572 (or 1548 counting only the distinct ones).

The product of its (nonzero) digits is 338688, while the sum is 45.

The square root of 1666707840 is about 40825.3333115604. Note that the first 4 decimals coincide. The cubic root of 1666707840 is about 1185.6408646932.

The spelling of 1666707840 in words is "one billion, six hundred sixty-six million, seven hundred seven thousand, eight hundred forty".