16721511663 has 8 divisors (see below), whose sum is σ = 22298180608. Its totient is φ = 11146258584.

The previous prime is 16721511641. The next prime is 16721511671. The reversal of 16721511663 is 36611512761.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 16721511663 - 2¹⁴ = 16721495279 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 (16721511613) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 326095 + ... + 373872.

It is an arithmetic number, because the mean of its divisors is an integer number (2787272576).

Almost surely, 2^16721511663 is an apocalyptic number.

16721511663 is a deficient number, since it is larger than the sum of its proper divisors (5576668945).

16721511663 is an equidigital number, since it uses as much as digits as its factorization.

16721511663 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 707933.

The product of its digits is 45360, while the sum is 39.

The spelling of 16721511663 in words is "sixteen billion, seven hundred twenty-one million, five hundred eleven thousand, six hundred sixty-three".