641440 has 48 divisors (see below), whose sum is σ = 1602720. Its totient is φ = 241920.

The previous prime is 641437. The next prime is 641441. The reversal of 641440 is 44146.

It is a super-2 number, since 2×641440² = 822890547200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (19).

It is not an unprimeable number, because it can be changed into a prime (641441) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2935 + ... + 3145.

It is an arithmetic number, because the mean of its divisors is an integer number (33390).

2⁶⁴¹⁴⁴⁰ is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 641440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (801360).

641440 is an abundant number, since it is smaller than the sum of its proper divisors (961280).

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

641440 is a wasteful number, since it uses less digits than its factorization.

641440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 245 (or 237 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 19.

The square root of 641440 is about 800.8994943187. The cubic root of 641440 is about 86.2419722277.

Adding to 641440 its reverse (44146), we get a palindrome (685586).

It can be divided in two parts, 641 and 440, that added together give a triangular number (1081 = T₄₆).

The spelling of 641440 in words is "six hundred forty-one thousand, four hundred forty".