9728918681 has 2 divisors, whose sum is σ = 9728918682. Its totient is φ = 9728918680.

The previous prime is 9728918671. The next prime is 9728918687. The reversal of 9728918681 is 1868198279.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 8025293056 + 1703625625 = 89584^2 + 41275^2 .

It is a cyclic number.

It is not a de Polignac number, because 9728918681 - 2¹⁴ = 9728902297 is a prime.

It is a super-2 number, since 2×9728918681² (a number of 21 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 9728918681.

It is not a weakly prime, because it can be changed into another prime (9728918687) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4864459340 + 4864459341.

It is an arithmetic number, because the mean of its divisors is an integer number (4864459341).

Almost surely, 2^9728918681 is an apocalyptic number.

It is an amenable number.

9728918681 is a deficient number, since it is larger than the sum of its proper divisors (1).

9728918681 is an equidigital number, since it uses as much as digits as its factorization.

9728918681 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3483648, while the sum is 59.

The square root of 9728918681 is about 98635.2811168499. The cubic root of 9728918681 is about 2134.7885155985.

The spelling of 9728918681 in words is "nine billion, seven hundred twenty-eight million, nine hundred eighteen thousand, six hundred eighty-one".