1666199808 has 360 divisors, whose sum is σ = 6121763648. Its totient is φ = 438939648.

The previous prime is 1666199797. The next prime is 1666199809. The reversal of 1666199808 is 8089916661.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is not an unprimeable number, because it can be changed into a prime (1666199809) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 1886535 + ... + 1887417.

Almost surely, 2^1666199808 is an apocalyptic number.

1666199808 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 1666199808, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3060881824).

1666199808 is an abundant number, since it is smaller than the sum of its proper divisors (4455563840).

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

1666199808 is an equidigital number, since it uses as much as digits as its factorization.

1666199808 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 931 (or 908 counting only the distinct ones).

The product of its (nonzero) digits is 1119744, while the sum is 54.

The square root of 1666199808 is about 40819.1108183410. The cubic root of 1666199808 is about 1185.5203867274.

The spelling of 1666199808 in words is "one billion, six hundred sixty-six million, one hundred ninety-nine thousand, eight hundred eight".