21293971308287 has 2 divisors, whose sum is σ = 21293971308288. Its totient is φ = 21293971308286.

The previous prime is 21293971308241. The next prime is 21293971308289. The reversal of 21293971308287 is 78280317939212.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21293971308287 - 2⁶ = 21293971308223 is a prime.

Together with 21293971308289, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21293971308289) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10646985654143 + 10646985654144.

It is an arithmetic number, because the mean of its divisors is an integer number (10646985654144).

Almost surely, 2^{21293971308287} is an apocalyptic number.

21293971308287 is a deficient number, since it is larger than the sum of its proper divisors (1).

21293971308287 is an equidigital number, since it uses as much as digits as its factorization.

21293971308287 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 18289152, while the sum is 62.

The spelling of 21293971308287 in words is "twenty-one trillion, two hundred ninety-three billion, nine hundred seventy-one million, three hundred eight thousand, two hundred eighty-seven".