1665636074640 has 240 divisors, whose sum is σ = 5976056049600. Its totient is φ = 414511561728.

The previous prime is 1665636074639. The next prime is 1665636074699. The reversal of 1665636074640 is 464706365661.

1665636074640 is a `hidden beast` number, since 1 + 6 + 6 + 563 + 6 + 0 + 74 + 6 + 4 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (240).

It is a super-2 number, since 2×1665636074640² (a number of 25 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 7926 + ... + 1825194.

It is an arithmetic number, because the mean of its divisors is an integer number (24900233540).

Almost surely, 2^{1665636074640} is an apocalyptic number.

1665636074640 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 1665636074640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2988028024800).

1665636074640 is an abundant number, since it is smaller than the sum of its proper divisors (4310419974960).

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

1665636074640 is a wasteful number, since it uses less digits than its factorization.

1665636074640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1817374 (or 1817365 counting only the distinct ones).

The product of its (nonzero) digits is 13063680, while the sum is 54.

The spelling of 1665636074640 in words is "one trillion, six hundred sixty-five billion, six hundred thirty-six million, seventy-four thousand, six hundred forty".