8921621978719 has 2 divisors, whose sum is σ = 8921621978720. Its totient is φ = 8921621978718.

The previous prime is 8921621978707. The next prime is 8921621978761. The reversal of 8921621978719 is 9178791261298.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 8921621978719 - 2¹¹ = 8921621976671 is a prime.

It is a super-3 number, since 3×8921621978719³ (a number of 40 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (8921621928719) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4460810989359 + 4460810989360.

It is an arithmetic number, because the mean of its divisors is an integer number (4460810989360).

Almost surely, 2^{8921621978719} is an apocalyptic number.

8921621978719 is a deficient number, since it is larger than the sum of its proper divisors (1).

8921621978719 is an equidigital number, since it uses as much as digits as its factorization.

8921621978719 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 54867456, while the sum is 70.

The spelling of 8921621978719 in words is "eight trillion, nine hundred twenty-one billion, six hundred twenty-one million, nine hundred seventy-eight thousand, seven hundred nineteen".