1638236407068 has 120 divisors (see below), whose sum is σ = 4335841407744. Its totient is φ = 539339018400.

The previous prime is 1638236407061. The next prime is 1638236407097. The reversal of 1638236407068 is 8607046328361.

It is a Smith number, since the sum of its digits (54) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1638236407061) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 8864221 + ... + 9047147.

Almost surely, 2^{1638236407068} is an apocalyptic number.

1638236407068 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1638236407068, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2167920703872).

1638236407068 is an abundant number, since it is smaller than the sum of its proper divisors (2697605000676).

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

1638236407068 is a wasteful number, since it uses less digits than its factorization.

1638236407068 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 183285 (or 183274 counting only the distinct ones).

The product of its (nonzero) digits is 6967296, while the sum is 54.

The spelling of 1638236407068 in words is "one trillion, six hundred thirty-eight billion, two hundred thirty-six million, four hundred seven thousand, sixty-eight".