2085866728009 has 9 divisors (see below), whose sum is σ = 2104653750069. Its totient is φ = 2067245974080.

The previous prime is 2085866727979. The next prime is 2085866728031. The reversal of 2085866728009 is 9008276685802.

The square root of 2085866728009 is 1444253.

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

It can be written as a sum of positive squares in 4 ways, for example, as 322357095225 + 1763509632784 = 567765^2 + 1327972^2 .

It is not a de Polignac number, because 2085866728009 - 2⁵ = 2085866727977 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2085866728039) 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, 163194199 + ... + 163206979.

Almost surely, 2^{2085866728009} is an apocalyptic number.

2085866728009 is the 1444253-rd square number.

2085866728009 is the 722127-th centered octagonal number.

It is an amenable number.

2085866728009 is a deficient number, since it is larger than the sum of its proper divisors (18787022060).

2085866728009 is an frugal number, since it uses more digits than its factorization.

2085866728009 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25788 (or 12894 counting only the distinct ones).

The product of its (nonzero) digits is 23224320, while the sum is 61.

The spelling of 2085866728009 in words is "two trillion, eighty-five billion, eight hundred sixty-six million, seven hundred twenty-eight thousand, nine".