668404840 has 32 divisors (see below), whose sum is σ = 1569300480. Its totient is φ = 255737152.

The previous prime is 668404823. The next prime is 668404843. The reversal of 668404840 is 48404866.

668404840 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (40).

It is a junction number, because it is equal to n+sod(n) for n = 668404793 and 668404802.

It is not an unprimeable number, because it can be changed into a prime (668404843) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 362344 + ... + 364183.

It is an arithmetic number, because the mean of its divisors is an integer number (49040640).

Almost surely, 2^668404840 is an apocalyptic number.

It is an amenable number.

668404840 is an abundant number, since it is smaller than the sum of its proper divisors (900895640).

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

668404840 is a wasteful number, since it uses less digits than its factorization.

668404840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 726561 (or 726557 counting only the distinct ones).

The product of its (nonzero) digits is 147456, while the sum is 40.

The square root of 668404840 is about 25853.5266453148. The cubic root of 668404840 is about 874.3390229991.

The spelling of 668404840 in words is "six hundred sixty-eight million, four hundred four thousand, eight hundred forty".