668481408 has 192 divisors, whose sum is σ = 2314665600. Its totient is φ = 180900864.

The previous prime is 668481377. The next prime is 668481481. The reversal of 668481408 is 804184866.

It is a tau number, because it is divible by the number of its divisors (192).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 151035 + ... + 155397.

It is an arithmetic number, because the mean of its divisors is an integer number (12055550).

Almost surely, 2^668481408 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 668481408, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1157332800).

668481408 is an abundant number, since it is smaller than the sum of its proper divisors (1646184192).

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

668481408 is a wasteful number, since it uses less digits than its factorization.

668481408 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4409 (or 4394 counting only the distinct ones).

The product of its (nonzero) digits is 294912, while the sum is 45.

The square root of 668481408 is about 25855.0074066901. The cubic root of 668481408 is about 874.3724078731.

The spelling of 668481408 in words is "six hundred sixty-eight million, four hundred eighty-one thousand, four hundred eight".