641749 has 2 divisors, whose sum is σ = 641750. Its totient is φ = 641748.

The previous prime is 641747. The next prime is 641761. The reversal of 641749 is 947146.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 476100 + 165649 = 690^2 + 407^2 .

It is a cyclic number.

It is not a de Polignac number, because 641749 - 2¹ = 641747 is a prime.

Together with 641747, it forms a pair of twin primes.

641749 is a lucky number.

It is a self number, because there is not a number n which added to its sum of digits gives 641749.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (641747) 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, 320874 + 320875.

It is an arithmetic number, because the mean of its divisors is an integer number (320875).

2⁶⁴¹⁷⁴⁹ is an apocalyptic number.

It is an amenable number.

641749 is a deficient number, since it is larger than the sum of its proper divisors (1).

641749 is an equidigital number, since it uses as much as digits as its factorization.

641749 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 6048, while the sum is 31.

The square root of 641749 is about 801.0923791923. The cubic root of 641749 is about 86.2558184131.

The spelling of 641749 in words is "six hundred forty-one thousand, seven hundred forty-nine".