21045647387 has 2 divisors, whose sum is σ = 21045647388. Its totient is φ = 21045647386.

The previous prime is 21045647353. The next prime is 21045647417. The reversal of 21045647387 is 78374654012.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21045647387 - 2¹⁴ = 21045631003 is a prime.

It is not a weakly prime, because it can be changed into another prime (21045647317) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10522823693 + 10522823694.

It is an arithmetic number, because the mean of its divisors is an integer number (10522823694).

Almost surely, 2^21045647387 is an apocalyptic number.

21045647387 is a deficient number, since it is larger than the sum of its proper divisors (1).

21045647387 is an equidigital number, since it uses as much as digits as its factorization.

21045647387 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1128960, while the sum is 47.

The spelling of 21045647387 in words is "twenty-one billion, forty-five million, six hundred forty-seven thousand, three hundred eighty-seven".