16556890663 has 4 divisors (see below), whose sum is σ = 16609120920. Its totient is φ = 16504660408.

The previous prime is 16556890613. The next prime is 16556890687. The reversal of 16556890663 is 36609865561.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 36609865561 = 12641 ⋅2896121.

It is a cyclic number.

It is not a de Polignac number, because 16556890663 - 2³³ = 7966956071 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16556890613) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 26114653 + ... + 26115286.

It is an arithmetic number, because the mean of its divisors is an integer number (4152280230).

Almost surely, 2^16556890663 is an apocalyptic number.

16556890663 is a deficient number, since it is larger than the sum of its proper divisors (52230257).

16556890663 is an equidigital number, since it uses as much as digits as its factorization.

16556890663 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 52230256.

The product of its (nonzero) digits is 6998400, while the sum is 55.

The spelling of 16556890663 in words is "sixteen billion, five hundred fifty-six million, eight hundred ninety thousand, six hundred sixty-three".