642240 has 84 divisors (see below), whose sum is σ = 2218944. Its totient is φ = 170496.

The previous prime is 642233. The next prime is 642241. The reversal of 642240 is 42246.

642240 is a `hidden beast` number, since 642 + 24 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is not an unprimeable number, because it can be changed into a prime (642241) by changing a digit.

642240 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, 2769 + ... + 2991.

It is an arithmetic number, because the mean of its divisors is an integer number (26416).

2⁶⁴²²⁴⁰ is an apocalyptic number.

642240 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 642240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1109472).

642240 is an abundant number, since it is smaller than the sum of its proper divisors (1576704).

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

642240 is a wasteful number, since it uses less digits than its factorization.

642240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 246 (or 233 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 18.

The square root of 642240 is about 801.3987771391. The cubic root of 642240 is about 86.2778108174.

Adding to 642240 its reverse (42246), we get a palindrome (684486).

It can be divided in two parts, 64 and 2240, that added together give a square (2304 = 48²).

The spelling of 642240 in words is "six hundred forty-two thousand, two hundred forty".