642400 has 72 divisors (see below), whose sum is σ = 1734264. Its totient is φ = 230400.

The previous prime is 642373. The next prime is 642403. The reversal of 642400 is 4246.

It is a Harshad number since it is a multiple of its sum of digits (16).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (642403) by changing a digit.

642400 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 8764 + ... + 8836.

It is an arithmetic number, because the mean of its divisors is an integer number (24087).

2⁶⁴²⁴⁰⁰ 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 642400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (867132).

642400 is an abundant number, since it is smaller than the sum of its proper divisors (1091864).

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

642400 is a wasteful number, since it uses less digits than its factorization.

642400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 104 (or 91 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 16.

The square root of 642400 is about 801.4985963806. The cubic root of 642400 is about 86.2849749634.

Adding to 642400 its reverse (4246), we get a palindrome (646646).

The spelling of 642400 in words is "six hundred forty-two thousand, four hundred".