1666811696256 has 384 divisors, whose sum is σ = 5720976293760. Its totient is φ = 473188884480.

The previous prime is 1666811696233. The next prime is 1666811696257. The reversal of 1666811696256 is 6526961186661.

It is a tau number, because it is divible by the number of its divisors (384).

It is a super-2 number, since 2×1666811696256² (a number of 25 digits) contains 22 as substring.

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 = 1666811696193 and 1666811696202.

It is not an unprimeable number, because it can be changed into a prime (1666811696257) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 34158916 + ... + 34207676.

It is an arithmetic number, because the mean of its divisors is an integer number (14898375765).

Almost surely, 2^{1666811696256} is an apocalyptic number.

1666811696256 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 1666811696256, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2860488146880).

1666811696256 is an abundant number, since it is smaller than the sum of its proper divisors (4054164597504).

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

1666811696256 is an equidigital number, since it uses as much as digits as its factorization.

1666811696256 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 48954 (or 48930 counting only the distinct ones).

The product of its digits is 33592320, while the sum is 63.

The spelling of 1666811696256 in words is "one trillion, six hundred sixty-six billion, eight hundred eleven million, six hundred ninety-six thousand, two hundred fifty-six".