1666615087680 has 224 divisors, whose sum is σ = 5424131115648. Its totient is φ = 433305600000.

The previous prime is 1666615087679. The next prime is 1666615087681. The reversal of 1666615087680 is 867805166661.

It is an interprime number because it is at equal distance from previous prime (1666615087679) and next prime (1666615087681).

It is a super-2 number, since 2×1666615087680² (a number of 25 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (60).

It is not an unprimeable number, because it can be changed into a prime (1666615087681) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 63474555 + ... + 63500805.

It is an arithmetic number, because the mean of its divisors is an integer number (24214871052).

Almost surely, 2^{1666615087680} is an apocalyptic number.

1666615087680 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 1666615087680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2712065557824).

1666615087680 is an abundant number, since it is smaller than the sum of its proper divisors (3757516027968).

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

1666615087680 is a wasteful number, since it uses less digits than its factorization.

1666615087680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27925 (or 27915 counting only the distinct ones).

The product of its (nonzero) digits is 17418240, while the sum is 60.

The spelling of 1666615087680 in words is "one trillion, six hundred sixty-six billion, six hundred fifteen million, eighty-seven thousand, six hundred eighty".