1666560406725 has 36 divisors (see below), whose sum is σ = 2985077174976. Its totient is φ = 888807707040.

The previous prime is 1666560406697. The next prime is 1666560406739. The reversal of 1666560406725 is 5276040656661.

It is not a de Polignac number, because 1666560406725 - 2⁷ = 1666560406597 is a prime.

It is a congruent number.

It is an unprimeable number.

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 35 ways as a sum of consecutive naturals, for example, 10529524 + ... + 10686626.

It is an arithmetic number, because the mean of its divisors is an integer number (82918810416).

Almost surely, 2^{1666560406725} is an apocalyptic number.

1666560406725 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1666560406725 is a deficient number, since it is larger than the sum of its proper divisors (1318516768251).

1666560406725 is a wasteful number, since it uses less digits than its factorization.

1666560406725 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 204266 (or 204258 counting only the distinct ones).

The product of its (nonzero) digits is 10886400, while the sum is 54.

The spelling of 1666560406725 in words is "one trillion, six hundred sixty-six billion, five hundred sixty million, four hundred six thousand, seven hundred twenty-five".