8721797786361 has 135 divisors (see below), whose sum is σ = 14982251017503. Its totient is φ = 5052216343680.

The previous prime is 8721797786347. The next prime is 8721797786371. The reversal of 8721797786361 is 1636877971278.

The square root of 8721797786361 is 2953269.

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

8721797786361 is a `hidden beast` number, since 87 + 21 + 7 + 97 + 7 + 86 + 361 = 666.

It can be written as a sum of positive squares in only one way, i.e., 8694920151225 + 26877635136 = 2948715^2 + 163944^2 .

It is a de Polignac number, because none of the positive numbers 2^k-8721797786361 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 8721797786361.

It is not an unprimeable number, because it can be changed into a prime (8721797786371) by changing a digit.

It is a polite number, since it can be written in 134 ways as a sum of consecutive naturals, for example, 6724592865 + ... + 6724594161.

Almost surely, 2^{8721797786361} is an apocalyptic number.

8721797786361 is a gapful number since it is divisible by the number (81) formed by its first and last digit.

8721797786361 is the 2953269-th square number.

8721797786361 is the 1476635-th centered octagonal number.

It is an amenable number.

8721797786361 is a deficient number, since it is larger than the sum of its proper divisors (6260453231142).

8721797786361 is an equidigital number, since it uses as much as digits as its factorization.

8721797786361 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2674 (or 1334 counting only the distinct ones).

The product of its digits is 298722816, while the sum is 72.

The spelling of 8721797786361 in words is "eight trillion, seven hundred twenty-one billion, seven hundred ninety-seven million, seven hundred eighty-six thousand, three hundred sixty-one".