1638387959040 has 1008 divisors, whose sum is σ = 6863130624000. Its totient is φ = 374415519744.

The previous prime is 1638387959029. The next prime is 1638387959041. The reversal of 1638387959040 is 409597838361.

1638387959040 is a `hidden beast` number, since 1 + 6 + 3 + 8 + 38 + 7 + 9 + 590 + 4 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (1008).

It is a Harshad number since it is a multiple of its sum of digits (63).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1638387959041) by changing a digit.

It is a polite number, since it can be written in 111 ways as a sum of consecutive naturals, for example, 320057601 + ... + 320062719.

Almost surely, 2^{1638387959040} is an apocalyptic number.

1638387959040 is a gapful number since it is divisible by the number (10) 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 1638387959040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3431565312000).

1638387959040 is an abundant number, since it is smaller than the sum of its proper divisors (5224742664960).

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

1638387959040 is an frugal number, since it uses more digits than its factorization.

1638387959040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5179 (or 5136 counting only the distinct ones).

The product of its (nonzero) digits is 39191040, while the sum is 63.

The spelling of 1638387959040 in words is "one trillion, six hundred thirty-eight billion, three hundred eighty-seven million, nine hundred fifty-nine thousand, forty".