1666038016503 has 36 divisors (see below), whose sum is σ = 2799499962168. Its totient is φ = 951986780640.

The previous prime is 1666038016499. The next prime is 1666038016519. The reversal of 1666038016503 is 3056108306661.

1666038016503 is a nontrivial binomial coefficient, being equal to C(1825398, 2).

It is not a de Polignac number, because 1666038016503 - 2² = 1666038016499 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1666038016103) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 16377868 + ... + 16479278.

It is an arithmetic number, because the mean of its divisors is an integer number (77763887838).

Almost surely, 2^{1666038016503} is an apocalyptic number.

1666038016503 is the 1825397-th triangular number and also the 912699-th hexagonal number.

1666038016503 is a deficient number, since it is larger than the sum of its proper divisors (1133461945665).

1666038016503 is a wasteful number, since it uses less digits than its factorization.

1666038016503 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 138684 (or 138674 counting only the distinct ones).

The product of its (nonzero) digits is 466560, while the sum is 45.

The spelling of 1666038016503 in words is "one trillion, six hundred sixty-six billion, thirty-eight million, sixteen thousand, five hundred three".