643495 has 16 divisors (see below), whose sum is σ = 820512. Its totient is φ = 483840.

The previous prime is 643493. The next prime is 643507. The reversal of 643495 is 594346.

It is not a de Polignac number, because 643495 - 2¹ = 643493 is a prime.

It is a Duffinian number.

Its product of digits (12960) is a multiple of the sum of its prime divisors (162).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643493) 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 in 15 ways as a sum of consecutive naturals, for example, 8779 + ... + 8851.

It is an arithmetic number, because the mean of its divisors is an integer number (51282).

2⁶⁴³⁴⁹⁵ is an apocalyptic number.

643495 is a deficient number, since it is larger than the sum of its proper divisors (177017).

643495 is a wasteful number, since it uses less digits than its factorization.

643495 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 162.

The product of its digits is 12960, while the sum is 31.

The square root of 643495 is about 802.1814009312. The cubic root of 643495 is about 86.3339726883. Note that the first 3 decimals are identical.

The spelling of 643495 in words is "six hundred forty-three thousand, four hundred ninety-five".