1661244173568 has 2016 divisors, whose sum is σ = 6588605399040. Its totient is φ = 406332702720.

The previous prime is 1661244173543. The next prime is 1661244173609. The reversal of 1661244173568 is 8653714421661.

1661244173568 is a `hidden beast` number, since 1 + 6 + 6 + 1 + 2 + 4 + 4 + 1 + 73 + 568 = 666.

It is a tau number, because it is divible by the number of its divisors (2016).

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 223 ways as a sum of consecutive naturals, for example, 13080662721 + ... + 13080662847.

It is an arithmetic number, because the mean of its divisors is an integer number (3268157440).

Almost surely, 2^{1661244173568} is an apocalyptic number.

1661244173568 is a gapful number since it is divisible by the number (18) 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 1661244173568, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3294302699520).

1661244173568 is an abundant number, since it is smaller than the sum of its proper divisors (4927361225472).

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

1661244173568 is a wasteful number, since it uses less digits than its factorization.

1661244173568 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 235 (or 206 counting only the distinct ones).

The product of its digits is 5806080, while the sum is 54.

The spelling of 1661244173568 in words is "one trillion, six hundred sixty-one billion, two hundred forty-four million, one hundred seventy-three thousand, five hundred sixty-eight".