217280905956 has 27 divisors (see below), whose sum is σ = 549244915401. Its totient is φ = 72426036384.

The previous prime is 217280905927. The next prime is 217280905967. The reversal of 217280905956 is 659509082712.

The square root of 217280905956 is 466134.

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

217280905956 is a `hidden beast` number, since 21 + 7 + 28 + 0 + 9 + 0 + 595 + 6 = 666.

217280905956 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 151580963556 + 65699942400 = 389334^2 + 256320^2 .

It is an unprimeable number.

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 8 ways as a sum of consecutive naturals, for example, 2757960 + ... + 2835648.

Almost surely, 2^217280905956 is an apocalyptic number.

217280905956 is the 466134-th square number.

It is an amenable number.

217280905956 is an abundant number, since it is smaller than the sum of its proper divisors (331964009445).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

217280905956 is an frugal number, since it uses more digits than its factorization.

217280905956 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 155388 (or 77694 counting only the distinct ones).

The product of its (nonzero) digits is 2721600, while the sum is 54.

The spelling of 217280905956 in words is "two hundred seventeen billion, two hundred eighty million, nine hundred five thousand, nine hundred fifty-six".