8439959681 has 4 divisors (see below), whose sum is σ = 8461007364. Its totient is φ = 8418912000.

The previous prime is 8439959669. The next prime is 8439959701. The reversal of 8439959681 is 1869599348.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 8371335025 + 68624656 = 91495^2 + 8284^2 .

It is a cyclic number.

It is not a de Polignac number, because 8439959681 - 2³⁰ = 7366217857 is a prime.

It is a super-2 number, since 2×8439959681² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (8439959611) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10523240 + ... + 10524041.

It is an arithmetic number, because the mean of its divisors is an integer number (2115251841).

Almost surely, 2^8439959681 is an apocalyptic number.

It is an amenable number.

8439959681 is a deficient number, since it is larger than the sum of its proper divisors (21047683).

8439959681 is a wasteful number, since it uses less digits than its factorization.

8439959681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21047682.

The product of its digits is 16796160, while the sum is 62.

The square root of 8439959681 is about 91869.2531862538. The cubic root of 8439959681 is about 2036.0110184539.

The spelling of 8439959681 in words is "eight billion, four hundred thirty-nine million, nine hundred fifty-nine thousand, six hundred eighty-one".