1668538368 has 336 divisors, whose sum is σ = 5704429536. Its totient is φ = 460062720.

The previous prime is 1668538367. The next prime is 1668538393. The reversal of 1668538368 is 8638358661.

1668538368 is a `hidden beast` number, since 16 + 68 + 538 + 36 + 8 = 666.

It is a tau number, because it is divible by the number of its divisors (336).

It is a Smith number, since the sum of its digits (54) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1668538363) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 27353058 + ... + 27353118.

Almost surely, 2^1668538368 is an apocalyptic number.

1668538368 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 1668538368, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2852214768).

1668538368 is an abundant number, since it is smaller than the sum of its proper divisors (4035891168).

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

1668538368 is an equidigital number, since it uses as much as digits as its factorization.

1668538368 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 153 (or 126 counting only the distinct ones).

The product of its digits is 4976640, while the sum is 54.

The square root of 1668538368 is about 40847.7461801750. The cubic root of 1668538368 is about 1186.0747649197.

The spelling of 1668538368 in words is "one billion, six hundred sixty-eight million, five hundred thirty-eight thousand, three hundred sixty-eight".