668736540 has 96 divisors (see below), whose sum is σ = 2190048000. Its totient is φ = 168941376.

The previous prime is 668736511. The next prime is 668736547. The reversal of 668736540 is 45637866.

668736540 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 (45).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (668736547) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 22330 + ... + 42849.

It is an arithmetic number, because the mean of its divisors is an integer number (22813000).

Almost surely, 2^668736540 is an apocalyptic number.

668736540 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

668736540 is an abundant number, since it is smaller than the sum of its proper divisors (1521311460).

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

668736540 is a wasteful number, since it uses less digits than its factorization.

668736540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 65216 (or 65208 counting only the distinct ones).

The product of its (nonzero) digits is 725760, while the sum is 45.

The square root of 668736540 is about 25859.9408351991. The cubic root of 668736540 is about 874.4836311145.

The spelling of 668736540 in words is "six hundred sixty-eight million, seven hundred thirty-six thousand, five hundred forty".