1666203557760 has 1024 divisors, whose sum is σ = 6921573120000. Its totient is φ = 378647764992.

The previous prime is 1666203557747. The next prime is 1666203557789. The reversal of 1666203557760 is 677553026661.

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

It is a junction number, because it is equal to n+sod(n) for n = 1666203557697 and 1666203557706.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 1167626167 + ... + 1167627593.

It is an arithmetic number, because the mean of its divisors is an integer number (6759348750).

Almost surely, 2^{1666203557760} is an apocalyptic number.

1666203557760 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 1666203557760, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3460786560000).

1666203557760 is an abundant number, since it is smaller than the sum of its proper divisors (5255369562240).

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

1666203557760 is a wasteful number, since it uses less digits than its factorization.

1666203557760 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1673 (or 1641 counting only the distinct ones).

The product of its (nonzero) digits is 9525600, while the sum is 54.

The spelling of 1666203557760 in words is "one trillion, six hundred sixty-six billion, two hundred three million, five hundred fifty-seven thousand, seven hundred sixty".