21717570678887 has 4 divisors (see below), whose sum is σ = 21721158586920. Its totient is φ = 21713982770856.

The previous prime is 21717570678803. The next prime is 21717570678901. The reversal of 21717570678887 is 78887607571712.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21717570678887 - 2²⁴ = 21717553901671 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21717576678887) 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 3 ways as a sum of consecutive naturals, for example, 1793944937 + ... + 1793957042.

It is an arithmetic number, because the mean of its divisors is an integer number (5430289646730).

Almost surely, 2^{21717570678887} is an apocalyptic number.

21717570678887 is a deficient number, since it is larger than the sum of its proper divisors (3587908033).

21717570678887 is an equidigital number, since it uses as much as digits as its factorization.

21717570678887 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3587908032.

The product of its (nonzero) digits is 516311040, while the sum is 74.

The spelling of 21717570678887 in words is "twenty-one trillion, seven hundred seventeen billion, five hundred seventy million, six hundred seventy-eight thousand, eight hundred eighty-seven".