667138335520 has 144 divisors (see below), whose sum is σ = 1628297524224. Its totient is φ = 258283468800.

The previous prime is 667138335509. The next prime is 667138335527. The reversal of 667138335520 is 25533831766.

It is not an unprimeable number, because it can be changed into a prime (667138335527) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 34148155 + ... + 34167685.

It is an arithmetic number, because the mean of its divisors is an integer number (11307621696).

Almost surely, 2^667138335520 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 667138335520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (814148762112).

667138335520 is an abundant number, since it is smaller than the sum of its proper divisors (961159188704).

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

667138335520 is a wasteful number, since it uses less digits than its factorization.

667138335520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19755 (or 19706 counting only the distinct ones).

The product of its (nonzero) digits is 2721600, while the sum is 49.

The spelling of 667138335520 in words is "six hundred sixty-seven billion, one hundred thirty-eight million, three hundred thirty-five thousand, five hundred twenty".