641999 has 8 divisors (see below), whose sum is σ = 678912. Its totient is φ = 605880.

The previous prime is 641981. The next prime is 642011. The reversal of 641999 is 999146.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-641999 is a prime.

It is an Ulam number.

It is a Duffinian number.

641999 is a modest number, since divided by 999 gives 641 as remainder.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 641999.

It is not an unprimeable number, because it can be changed into a prime (641909) 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 7 ways as a sum of consecutive naturals, for example, 2234 + ... + 2504.

It is an arithmetic number, because the mean of its divisors is an integer number (84864).

2⁶⁴¹⁹⁹⁹ is an apocalyptic number.

641999 is a deficient number, since it is larger than the sum of its proper divisors (36913).

641999 is a wasteful number, since it uses less digits than its factorization.

641999 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 397.

The product of its digits is 17496, while the sum is 38.

The square root of 641999 is about 801.2484009344. The cubic root of 641999 is about 86.2670175761.

The spelling of 641999 in words is "six hundred forty-one thousand, nine hundred ninety-nine".