16991643904 has 27 divisors (see below), whose sum is σ = 33921077827. Its totient is φ = 8494779136.

The previous prime is 16991643901. The next prime is 16991643913. The reversal of 16991643904 is 40934619961.

The square root of 16991643904 is 130352.

It is a perfect power (a square), and thus also a powerful number.

16991643904 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a super-2 number, since 2×16991643904² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (16991643901) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 2081559 + ... + 2089705.

Almost surely, 2^16991643904 is an apocalyptic number.

16991643904 is the 130352-nd square number.

It is an amenable number.

16991643904 is a deficient number, since it is larger than the sum of its proper divisors (16929433923).

16991643904 is an frugal number, since it uses more digits than its factorization.

16991643904 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16310 (or 8149 counting only the distinct ones).

The product of its (nonzero) digits is 1259712, while the sum is 52.

The spelling of 16991643904 in words is "sixteen billion, nine hundred ninety-one million, six hundred forty-three thousand, nine hundred four".