1666439705520 has 240 divisors, whose sum is σ = 5997618574272. Its totient is φ = 413574543360.

The previous prime is 1666439705519. The next prime is 1666439705531. The reversal of 1666439705520 is 255079346661.

It is a tau number, because it is divible by the number of its divisors (240).

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 747151 + ... + 1972590.

Almost surely, 2^{1666439705520} is an apocalyptic number.

1666439705520 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1666439705520 is an abundant number, since it is smaller than the sum of its proper divisors (4331178868752).

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

1666439705520 is a wasteful number, since it uses less digits than its factorization.

1666439705520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2719820 (or 2719811 counting only the distinct ones).

The product of its (nonzero) digits is 8164800, while the sum is 54.

The spelling of 1666439705520 in words is "one trillion, six hundred sixty-six billion, four hundred thirty-nine million, seven hundred five thousand, five hundred twenty".