647531 has 2 divisors, whose sum is σ = 647532. Its totient is φ = 647530.

The previous prime is 647527. The next prime is 647551. The reversal of 647531 is 135746.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 647531 - 2² = 647527 is a prime.

It is a super-2 number, since 2×647531² = 838592791922, which contains 22 as substring.

It is a Chen prime.

It is an Ulam number.

It is a self number, because there is not a number n which added to its sum of digits gives 647531.

It is not a weakly prime, because it can be changed into another prime (647551) 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, 323765 + 323766.

It is an arithmetic number, because the mean of its divisors is an integer number (323766).

2⁶⁴⁷⁵³¹ is an apocalyptic number.

647531 is a deficient number, since it is larger than the sum of its proper divisors (1).

647531 is an equidigital number, since it uses as much as digits as its factorization.

647531 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2520, while the sum is 26.

The square root of 647531 is about 804.6931092038. The cubic root of 647531 is about 86.5140921721.

The spelling of 647531 in words is "six hundred forty-seven thousand, five hundred thirty-one".