42644240 has 20 divisors (see below), whose sum is σ = 99148044. Its totient is φ = 17057664.

The previous prime is 42644237. The next prime is 42644243. The reversal of 42644240 is 4244624.

It is an interprime number because it is at equal distance from previous prime (42644237) and next prime (42644243).

It can be written as a sum of positive squares in 2 ways, for example, as 19642624 + 23001616 = 4432^2 + 4796^2 .

It is a tau number, because it is divible by the number of its divisors (20).

It is a hoax number, since the sum of its digits (26) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (42644243) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 266447 + ... + 266606.

Almost surely, 2^42644240 is an apocalyptic number.

42644240 is a gapful number since it is divisible by the number (40) formed by its first and last digit.

It is an amenable number.

42644240 is an abundant number, since it is smaller than the sum of its proper divisors (56503804).

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

42644240 is a wasteful number, since it uses less digits than its factorization.

42644240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 533066 (or 533060 counting only the distinct ones).

The product of its (nonzero) digits is 6144, while the sum is 26.

The square root of 42644240 is about 6530.2557377181. The cubic root of 42644240 is about 349.3709517336.

Adding to 42644240 its reverse (4244624), we get a palindrome (46888864).

The spelling of 42644240 in words is "forty-two million, six hundred forty-four thousand, two hundred forty".