668137520 has 20 divisors (see below), whose sum is σ = 1553419920. Its totient is φ = 267254976.

The previous prime is 668137487. The next prime is 668137529. The reversal of 668137520 is 25731866.

668137520 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a tau number, because it is divible by the number of its divisors (20).

It is not an unprimeable number, because it can be changed into a prime (668137529) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4175780 + ... + 4175939.

It is an arithmetic number, because the mean of its divisors is an integer number (77670996).

Almost surely, 2^668137520 is an apocalyptic number.

It is an amenable number.

668137520 is an abundant number, since it is smaller than the sum of its proper divisors (885282400).

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

668137520 is a wasteful number, since it uses less digits than its factorization.

668137520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8351732 (or 8351726 counting only the distinct ones).

The product of its (nonzero) digits is 60480, while the sum is 38.

The square root of 668137520 is about 25848.3562340045. The cubic root of 668137520 is about 874.2224472057. Note that the first 3 decimals are identical.

The spelling of 668137520 in words is "six hundred sixty-eight million, one hundred thirty-seven thousand, five hundred twenty".