864139427281 has 27 divisors (see below), whose sum is σ = 978492220209. Its totient is φ = 762740570592.

The previous prime is 864139427269. The next prime is 864139427339. The reversal of 864139427281 is 182724931468.

The square root of 864139427281 is 929591.

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 394114006225 + 470025421056 = 627785^2 + 685584^2 .

It is not a de Polignac number, because 864139427281 - 2²⁵ = 864105872849 is a prime.

It is a super-2 number, since 2×864139427281² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (864139427581) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 277946155 + ... + 277949263.

Almost surely, 2^864139427281 is an apocalyptic number.

864139427281 is the 929591-st square number.

864139427281 is the 464796-th centered octagonal number.

It is an amenable number.

864139427281 is a deficient number, since it is larger than the sum of its proper divisors (114352792928).

864139427281 is an frugal number, since it uses more digits than its factorization.

864139427281 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6290 (or 3145 counting only the distinct ones).

The product of its digits is 4644864, while the sum is 55.

The spelling of 864139427281 in words is "eight hundred sixty-four billion, one hundred thirty-nine million, four hundred twenty-seven thousand, two hundred eighty-one".