641820 has 48 divisors (see below), whose sum is σ = 1895040. Its totient is φ = 161856.

The previous prime is 641819. The next prime is 641821. The reversal of 641820 is 28146.

641820 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

641820 is an esthetic number in base 8, because in such base its adjacent digits differ by 1.

It is an interprime number because it is at equal distance from previous prime (641819) and next prime (641821).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (641821) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 859 + ... + 1421.

It is an arithmetic number, because the mean of its divisors is an integer number (39480).

2⁶⁴¹⁸²⁰ is an apocalyptic number.

641820 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 641820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (947520).

641820 is an abundant number, since it is smaller than the sum of its proper divisors (1253220).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

641820 is a wasteful number, since it uses less digits than its factorization.

641820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 594 (or 592 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 21.

The square root of 641820 is about 801.1366924564. The cubic root of 641820 is about 86.2589992710.

Adding to 641820 its reverse (28146), we get a palindrome (669966).

The spelling of 641820 in words is "six hundred forty-one thousand, eight hundred twenty".