668771840 has 240 divisors, whose sum is σ = 1880879616. Its totient is φ = 227082240.

The previous prime is 668771821. The next prime is 668771863. The reversal of 668771840 is 48177866.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 5265857 + ... + 5265983.

Almost surely, 2^668771840 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 668771840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (940439808).

668771840 is an abundant number, since it is smaller than the sum of its proper divisors (1212107776).

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

668771840 is a wasteful number, since it uses less digits than its factorization.

668771840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 189 (or 162 counting only the distinct ones).

The product of its (nonzero) digits is 451584, while the sum is 47.

The square root of 668771840 is about 25860.6233490224. The cubic root of 668771840 is about 874.4990177065.

The spelling of 668771840 in words is "six hundred sixty-eight million, seven hundred seventy-one thousand, eight hundred forty".