8691273978921 has 12 divisors (see below), whose sum is σ = 12665160312948. Its totient is φ = 5742906699264.

The previous prime is 8691273978911. The next prime is 8691273978923. The reversal of 8691273978921 is 1298793721968.

It can be written as a sum of positive squares in 2 ways, for example, as 4262820915600 + 4428453063321 = 2064660^2 + 2104389^2 .

It is a de Polignac number, because none of the positive numbers 2^k-8691273978921 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 8691273978921.

It is not an unprimeable number, because it can be changed into a prime (8691273978923) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 4272995040 + ... + 4272997073.

It is an arithmetic number, because the mean of its divisors is an integer number (1055430026079).

Almost surely, 2^{8691273978921} is an apocalyptic number.

It is an amenable number.

8691273978921 is a deficient number, since it is larger than the sum of its proper divisors (3973886334027).

8691273978921 is a wasteful number, since it uses less digits than its factorization.

8691273978921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8545992232 (or 8545992229 counting only the distinct ones).

The product of its digits is 164602368, while the sum is 72.

The spelling of 8691273978921 in words is "eight trillion, six hundred ninety-one billion, two hundred seventy-three million, nine hundred seventy-eight thousand, nine hundred twenty-one".