42728610681 has 9 divisors (see below), whose sum is σ = 61720000069. Its totient is φ = 28485327036.

The previous prime is 42728610623. The next prime is 42728610721. The reversal of 42728610681 is 18601682724.

The square root of 42728610681 is 206709.

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

42728610681 is a `hidden beast` number, since 4 + 2 + 7 + 28 + 610 + 6 + 8 + 1 = 666.

It is a tau number, because it is divible by the number of its divisors (9).

It is not a de Polignac number, because 42728610681 - 2¹³ = 42728602489 is a prime.

It is a super-2 number, since 2×42728610681² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (42728650681) 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, 585676 + ... + 654578.

Almost surely, 2^42728610681 is an apocalyptic number.

42728610681 is the 206709-th square number.

42728610681 is the 103355-th centered octagonal number.

It is an amenable number.

42728610681 is a deficient number, since it is larger than the sum of its proper divisors (18991389388).

42728610681 is an frugal number, since it uses more digits than its factorization.

42728610681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 137812 (or 68906 counting only the distinct ones).

The product of its (nonzero) digits is 258048, while the sum is 45.

The spelling of 42728610681 in words is "forty-two billion, seven hundred twenty-eight million, six hundred ten thousand, six hundred eighty-one".