2180208761809 has 15 divisors (see below), whose sum is σ = 2362156826487. Its totient is φ = 2012270053248.

The previous prime is 2180208761779. The next prime is 2180208761813. The reversal of 2180208761809 is 9081678020812.

It is a happy number.

The square root of 2180208761809 is 1476553.

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

It can be written as a sum of positive squares in 7 ways, for example, as 2149698454225 + 30510307584 = 1466185^2 + 174672^2 .

It is not a de Polignac number, because 2180208761809 - 2⁷ = 2180208761681 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2180208761609) by changing a digit.

It is a polite number, since it can be written in 14 ways as a sum of consecutive naturals, for example, 249533089 + ... + 249541825.

Almost surely, 2^{2180208761809} is an apocalyptic number.

2180208761809 is the 1476553-rd square number.

2180208761809 is the 738277-th centered octagonal number.

It is an amenable number.

2180208761809 is a deficient number, since it is larger than the sum of its proper divisors (181948064678).

2180208761809 is an frugal number, since it uses more digits than its factorization.

2180208761809 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17526 (or 8750 counting only the distinct ones).

The product of its (nonzero) digits is 774144, while the sum is 52.

The spelling of 2180208761809 in words is "two trillion, one hundred eighty billion, two hundred eight million, seven hundred sixty-one thousand, eight hundred nine".