168518440638 has 24 divisors (see below), whose sum is σ = 365159857608. Its totient is φ = 56167187472.

The previous prime is 168518440631. The next prime is 168518440703. The reversal of 168518440638 is 836044815861.

168518440638 is a `hidden beast` number, since 1 + 68 + 518 + 4 + 4 + 0 + 63 + 8 = 666.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (168518440631) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 282120 + ... + 645467.

It is an arithmetic number, because the mean of its divisors is an integer number (15214994067).

Almost surely, 2^168518440638 is an apocalyptic number.

168518440638 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

168518440638 is an abundant number, since it is smaller than the sum of its proper divisors (196641416970).

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

168518440638 is a wasteful number, since it uses less digits than its factorization.

168518440638 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 937688 (or 937685 counting only the distinct ones).

The product of its (nonzero) digits is 4423680, while the sum is 54.

The spelling of 168518440638 in words is "one hundred sixty-eight billion, five hundred eighteen million, four hundred forty thousand, six hundred thirty-eight".