21040320321247 has 2 divisors, whose sum is σ = 21040320321248. Its totient is φ = 21040320321246.

The previous prime is 21040320321157. The next prime is 21040320321263. The reversal of 21040320321247 is 74212302304012.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21040320321247 - 2³⁵ = 21005960582879 is a prime.

It is a super-3 number, since 3×21040320321247³ (a number of 41 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21040320321547) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10520160160623 + 10520160160624.

It is an arithmetic number, because the mean of its divisors is an integer number (10520160160624).

Almost surely, 2^{21040320321247} is an apocalyptic number.

21040320321247 is a deficient number, since it is larger than the sum of its proper divisors (1).

21040320321247 is an equidigital number, since it uses as much as digits as its factorization.

21040320321247 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 16128, while the sum is 31.

Adding to 21040320321247 its reverse (74212302304012), we get a palindrome (95252622625259).

The spelling of 21040320321247 in words is "twenty-one trillion, forty billion, three hundred twenty million, three hundred twenty-one thousand, two hundred forty-seven".