668212440 has 256 divisors, whose sum is σ = 2406481920. Its totient is φ = 145221120.

The previous prime is 668212427. The next prime is 668212459. The reversal of 668212440 is 44212866.

668212440 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 1744489 + ... + 1744871.

It is an arithmetic number, because the mean of its divisors is an integer number (9400320).

Almost surely, 2^668212440 is an apocalyptic number.

668212440 is a gapful number since it is divisible by the number (60) 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 668212440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1203240960).

668212440 is an abundant number, since it is smaller than the sum of its proper divisors (1738269480).

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

668212440 is a wasteful number, since it uses less digits than its factorization.

668212440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 502 (or 498 counting only the distinct ones).

The product of its (nonzero) digits is 18432, while the sum is 33.

The square root of 668212440 is about 25849.8054151284. The cubic root of 668212440 is about 874.2551222643.

The spelling of 668212440 in words is "six hundred sixty-eight million, two hundred twelve thousand, four hundred forty".