21023255387 has 2 divisors, whose sum is σ = 21023255388. Its totient is φ = 21023255386.

The previous prime is 21023255371. The next prime is 21023255423. The reversal of 21023255387 is 78355232012.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21023255387 - 2⁴ = 21023255371 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21023255387.

It is not a weakly prime, because it can be changed into another prime (21023255347) 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 as a sum of consecutive naturals, namely, 10511627693 + 10511627694.

It is an arithmetic number, because the mean of its divisors is an integer number (10511627694).

Almost surely, 2^21023255387 is an apocalyptic number.

21023255387 is a deficient number, since it is larger than the sum of its proper divisors (1).

21023255387 is an equidigital number, since it uses as much as digits as its factorization.

21023255387 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 100800, while the sum is 38.

Adding to 21023255387 its reverse (78355232012), we get a palindrome (99378487399).

The spelling of 21023255387 in words is "twenty-one billion, twenty-three million, two hundred fifty-five thousand, three hundred eighty-seven".