21703356287 has 2 divisors, whose sum is σ = 21703356288. Its totient is φ = 21703356286.

The previous prime is 21703356253. The next prime is 21703356293. The reversal of 21703356287 is 78265330712.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21703356287 - 2¹⁸ = 21703094143 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21703356247) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10851678143 + 10851678144.

It is an arithmetic number, because the mean of its divisors is an integer number (10851678144).

Almost surely, 2^21703356287 is an apocalyptic number.

21703356287 is a deficient number, since it is larger than the sum of its proper divisors (1).

21703356287 is an equidigital number, since it uses as much as digits as its factorization.

21703356287 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 423360, while the sum is 44.

Adding to 21703356287 its reverse (78265330712), we get a palindrome (99968686999).

The spelling of 21703356287 in words is "twenty-one billion, seven hundred three million, three hundred fifty-six thousand, two hundred eighty-seven".