9718475797809 has 33 divisors (see below), whose sum is σ = 14578767796683. Its totient is φ = 6478478838792.

The previous prime is 9718475797801. The next prime is 9718475797817. The reversal of 9718475797809 is 9087975748179.

The square root of 9718475797809 is 3117447.

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

9718475797809 is a `hidden beast` number, since 9 + 7 + 1 + 8 + 475 + 79 + 78 + 0 + 9 = 666.

It is an interprime number because it is at equal distance from previous prime (9718475797801) and next prime (9718475797817).

It can be written as a sum of positive squares in only one way, i.e., 7635014501409 + 2083461296400 = 2763153^2 + 1443420^2 .

It is not a de Polignac number, because 9718475797809 - 2³ = 9718475797801 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (81).

It is not an unprimeable number, because it can be changed into a prime (9718475797801) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 32 ways as a sum of consecutive naturals, for example, 757533207 + ... + 757546035.

Almost surely, 2^{9718475797809} is an apocalyptic number.

9718475797809 is the 3117447-th square number.

9718475797809 is the 1558724-th centered octagonal number.

It is an amenable number.

9718475797809 is a deficient number, since it is larger than the sum of its proper divisors (4860291998874).

9718475797809 is an frugal number, since it uses more digits than its factorization.

9718475797809 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25688 (or 12832 counting only the distinct ones).

The product of its (nonzero) digits is 2240421120, while the sum is 81.

Multiplying 9718475797809 by its sum of digits (81), we get a square (787196539622529 = 28057023²).

9718475797809 divided by its sum of digits (81) gives a square (119981182689 = 346383²).

The spelling of 9718475797809 in words is "nine trillion, seven hundred eighteen billion, four hundred seventy-five million, seven hundred ninety-seven thousand, eight hundred nine".