16663543556 has 36 divisors (see below), whose sum is σ = 32070510780. Its totient is φ = 7570252800.

The previous prime is 16663543541. The next prime is 16663543583. The reversal of 16663543556 is 65534536661.

It can be written as a sum of positive squares in 2 ways, for example, as 11058625600 + 5604917956 = 105160^2 + 74866^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1002836 + ... + 1019316.

Almost surely, 2^16663543556 is an apocalyptic number.

It is an amenable number.

16663543556 is a deficient number, since it is larger than the sum of its proper divisors (15406967224).

16663543556 is a wasteful number, since it uses less digits than its factorization.

16663543556 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18596 (or 18583 counting only the distinct ones).

The product of its digits is 5832000, while the sum is 50.

The spelling of 16663543556 in words is "sixteen billion, six hundred sixty-three million, five hundred forty-three thousand, five hundred fifty-six".