1665081419616 has 252 divisors, whose sum is σ = 5032034758548. Its totient is φ = 542105488512.

The previous prime is 1665081419611. The next prime is 1665081419621. The reversal of 1665081419616 is 6169141805661.

1665081419616 is a `hidden beast` number, since 1 + 6 + 6 + 5 + 0 + 8 + 1 + 4 + 19 + 616 = 666.

It is an interprime number because it is at equal distance from previous prime (1665081419611) and next prime (1665081419621).

It is a super-2 number, since 2×1665081419616² (a number of 25 digits) contains 22 as substring.

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 (1665081419611) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 41 ways as a sum of consecutive naturals, for example, 43114171 + ... + 43152773.

It is an arithmetic number, because the mean of its divisors is an integer number (19968391899).

Almost surely, 2^{1665081419616} is an apocalyptic number.

1665081419616 is a gapful number since it is divisible by the number (16) 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 1665081419616, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2516017379274).

1665081419616 is an abundant number, since it is smaller than the sum of its proper divisors (3366953338932).

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

1665081419616 is an frugal number, since it uses more digits than its factorization.

1665081419616 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 38717 (or 38651 counting only the distinct ones).

The product of its (nonzero) digits is 1866240, while the sum is 54.

The spelling of 1665081419616 in words is "one trillion, six hundred sixty-five billion, eighty-one million, four hundred nineteen thousand, six hundred sixteen".