647551 has 2 divisors, whose sum is σ = 647552. Its totient is φ = 647550.

The previous prime is 647531. The next prime is 647557. The reversal of 647551 is 155746.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 647551 - 2⁹ = 647039 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (647557) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 323775 + 323776.

It is an arithmetic number, because the mean of its divisors is an integer number (323776).

2⁶⁴⁷⁵⁵¹ is an apocalyptic number.

647551 is a deficient number, since it is larger than the sum of its proper divisors (1).

647551 is an equidigital number, since it uses as much as digits as its factorization.

647551 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4200, while the sum is 28.

The square root of 647551 is about 804.7055362056. The cubic root of 647551 is about 86.5149828702.

The spelling of 647551 in words is "six hundred forty-seven thousand, five hundred fifty-one".