1666646748 has 144 divisors (see below), whose sum is σ = 4827828096. Its totient is φ = 480245760.

The previous prime is 1666646719. The next prime is 1666646749. The reversal of 1666646748 is 8476466661.

It is a happy number.

It is a super-2 number, since 2×1666646748² = 5555422765237951008, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 1666646694 and 1666646703.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1666646749) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 2155690 + ... + 2156462.

It is an arithmetic number, because the mean of its divisors is an integer number (33526584).

Almost surely, 2^1666646748 is an apocalyptic number.

1666646748 is a gapful number since it is divisible by the number (18) 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 1666646748, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2413914048).

1666646748 is an abundant number, since it is smaller than the sum of its proper divisors (3161181348).

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

1666646748 is a wasteful number, since it uses less digits than its factorization.

1666646748 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1084 (or 1079 counting only the distinct ones).

The product of its digits is 6967296, while the sum is 54.

The square root of 1666646748 is about 40824.5850928090. The cubic root of 1666646748 is about 1185.6263782397.

The spelling of 1666646748 in words is "one billion, six hundred sixty-six million, six hundred forty-six thousand, seven hundred forty-eight".