647504521 has 2 divisors, whose sum is σ = 647504522. Its totient is φ = 647504520.

The previous prime is 647504519. The next prime is 647504537. The reversal of 647504521 is 125405746.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 482022025 + 165482496 = 21955^2 + 12864^2 .

It is a cyclic number.

It is not a de Polignac number, because 647504521 - 2¹ = 647504519 is a prime.

Together with 647504519, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (647504321) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 323752260 + 323752261.

It is an arithmetic number, because the mean of its divisors is an integer number (323752261).

Almost surely, 2^647504521 is an apocalyptic number.

It is an amenable number.

647504521 is a deficient number, since it is larger than the sum of its proper divisors (1).

647504521 is an equidigital number, since it uses as much as digits as its factorization.

647504521 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 33600, while the sum is 34.

The square root of 647504521 is about 25446.1101349499. The cubic root of 647504521 is about 865.1291290401.

It can be divided in two parts, 647504 and 521, that added together give a square (648025 = 805²).

The spelling of 647504521 in words is "six hundred forty-seven million, five hundred four thousand, five hundred twenty-one".