664168428 has 288 divisors, whose sum is σ = 2214051840. Its totient is φ = 162864000.

The previous prime is 664168403. The next prime is 664168429. The reversal of 664168428 is 824861466.

664168428 is a `hidden beast` number, since 6 + 64 + 168 + 428 = 666.

It is a super-3 number, since 3×664168428³ (a number of 27 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is not an unprimeable number, because it can be changed into a prime (664168429) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 5069923 + ... + 5070053.

It is an arithmetic number, because the mean of its divisors is an integer number (7687680).

Almost surely, 2^664168428 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 664168428, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1107025920).

664168428 is an abundant number, since it is smaller than the sum of its proper divisors (1549883412).

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

664168428 is a wasteful number, since it uses less digits than its factorization.

664168428 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 249 (or 244 counting only the distinct ones).

The product of its digits is 442368, while the sum is 45.

The square root of 664168428 is about 25771.4653832490. The cubic root of 664168428 is about 872.4878925970.

The spelling of 664168428 in words is "six hundred sixty-four million, one hundred sixty-eight thousand, four hundred twenty-eight".