641663 has 6 divisors (see below), whose sum is σ = 705432. Its totient is φ = 583220.

The previous prime is 641639. The next prime is 641681. The reversal of 641663 is 366146.

It is not a de Polignac number, because 641663 - 2¹⁴ = 625279 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (641623) 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 in 5 ways as a sum of consecutive naturals, for example, 2531 + ... + 2772.

It is an arithmetic number, because the mean of its divisors is an integer number (117572).

2⁶⁴¹⁶⁶³ is an apocalyptic number.

641663 is a deficient number, since it is larger than the sum of its proper divisors (63769).

641663 is a wasteful number, since it uses less digits than its factorization.

641663 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5325 (or 5314 counting only the distinct ones).

The product of its digits is 2592, while the sum is 26.

The square root of 641663 is about 801.0387006881. The cubic root of 641663 is about 86.2519652286.

The spelling of 641663 in words is "six hundred forty-one thousand, six hundred sixty-three".