1665964371456 has 800 divisors, whose sum is σ = 6399798958080. Its totient is φ = 418734489600.

The previous prime is 1665964371427. The next prime is 1665964371457. The reversal of 1665964371456 is 6541734695661.

It is a happy number.

1665964371456 is a `hidden beast` number, since 1 + 6 + 6 + 59 + 6 + 437 + 145 + 6 = 666.

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

It is a junction number, because it is equal to n+sod(n) for n = 1665964371393 and 1665964371402.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1665964371457) 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 79 ways as a sum of consecutive naturals, for example, 98985250 + ... + 99002078.

Almost surely, 2^{1665964371456} is an apocalyptic number.

1665964371456 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 1665964371456, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3199899479040).

1665964371456 is an abundant number, since it is smaller than the sum of its proper divisors (4733834586624).

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

1665964371456 is a wasteful number, since it uses less digits than its factorization.

1665964371456 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16908 (or 16883 counting only the distinct ones).

The product of its digits is 97977600, while the sum is 63.

The spelling of 1665964371456 in words is "one trillion, six hundred sixty-five billion, nine hundred sixty-four million, three hundred seventy-one thousand, four hundred fifty-six".