646537 has 2 divisors, whose sum is σ = 646538. Its totient is φ = 646536.

The previous prime is 646523. The next prime is 646543. The reversal of 646537 is 735646.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 646416 + 121 = 804^2 + 11^2 .

It is a cyclic number.

It is not a de Polignac number, because 646537 - 2¹¹ = 644489 is a prime.

646537 is a lucky number.

It is a nialpdrome in base 15.

It is a junction number, because it is equal to n+sod(n) for n = 646499 and 646508.

It is not a weakly prime, because it can be changed into another prime (646577) 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, 323268 + 323269.

It is an arithmetic number, because the mean of its divisors is an integer number (323269).

2⁶⁴⁶⁵³⁷ is an apocalyptic number.

It is an amenable number.

646537 is a deficient number, since it is larger than the sum of its proper divisors (1).

646537 is an equidigital number, since it uses as much as digits as its factorization.

646537 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 15120, while the sum is 31.

The square root of 646537 is about 804.0752452352. The cubic root of 646537 is about 86.4698013465.

The spelling of 646537 in words is "six hundred forty-six thousand, five hundred thirty-seven".