16991904609 has 9 divisors (see below), whose sum is σ = 24544427089. Its totient is φ = 11327675700.

The previous prime is 16991904607. The next prime is 16991904619. The reversal of 16991904609 is 90640919961.

The square root of 16991904609 is 130353.

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

16991904609 is a `hidden beast` number, since 1 + 6 + 9 + 91 + 90 + 460 + 9 = 666.

It is a tau number, because it is divible by the number of its divisors (9).

It is not a de Polignac number, because 16991904609 - 2¹ = 16991904607 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (16991904607) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 369334 + ... + 412784.

Almost surely, 2^16991904609 is an apocalyptic number.

16991904609 is the 130353-rd square number.

16991904609 is the 65177-th centered octagonal number.

It is an amenable number.

16991904609 is a deficient number, since it is larger than the sum of its proper divisors (7552522480).

16991904609 is an frugal number, since it uses more digits than its factorization.

16991904609 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 86908 (or 43454 counting only the distinct ones).

The product of its (nonzero) digits is 944784, while the sum is 54.

It can be divided in two parts, 16991 and 904609, that added together give a square (921600 = 960²).

The spelling of 16991904609 in words is "sixteen billion, nine hundred ninety-one million, nine hundred four thousand, six hundred nine".