17956804009 has 9 divisors (see below), whose sum is σ = 18146782839. Its totient is φ = 17768797800.

The previous prime is 17956804001. The next prime is 17956804037. The reversal of 17956804009 is 90040865971.

The square root of 17956804009 is 134003.

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

It can be written as a sum of positive squares in only one way, i.e., 27594009 + 17929210000 = 5253^2 + 133900^2 .

It is not a de Polignac number, because 17956804009 - 2³ = 17956804001 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (17956804001) 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 8 ways as a sum of consecutive naturals, for example, 13801659 + ... + 13802959.

Almost surely, 2^17956804009 is an apocalyptic number.

17956804009 is the 134003-rd square number.

17956804009 is the 67002-nd centered octagonal number.

It is an amenable number.

17956804009 is a deficient number, since it is larger than the sum of its proper divisors (189978830).

17956804009 is an frugal number, since it uses more digits than its factorization.

17956804009 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2808 (or 1404 counting only the distinct ones).

The product of its (nonzero) digits is 544320, while the sum is 49.

Multiplying 17956804009 by its sum of digits (49), we get a square (879883396441 = 938021²).

The spelling of 17956804009 in words is "seventeen billion, nine hundred fifty-six million, eight hundred four thousand, nine".