42123440 has 20 divisors (see below), whose sum is σ = 97937184. Its totient is φ = 16849344.

The previous prime is 42123401. The next prime is 42123449. The reversal of 42123440 is 4432124.

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

It is a Harshad number since it is a multiple of its sum of digits (20).

It is not an unprimeable number, because it can be changed into a prime (42123449) 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, 263192 + ... + 263351.

Almost surely, 2^42123440 is an apocalyptic number.

42123440 is a gapful number since it is divisible by the number (40) formed by its first and last digit.

It is an amenable number.

42123440 is an abundant number, since it is smaller than the sum of its proper divisors (55813744).

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

42123440 is a wasteful number, since it uses less digits than its factorization.

42123440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 526556 (or 526550 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 20.

The square root of 42123440 is about 6490.2573138513. The cubic root of 42123440 is about 347.9428716721.

Adding to 42123440 its reverse (4432124), we get a palindrome (46555564).

The spelling of 42123440 in words is "forty-two million, one hundred twenty-three thousand, four hundred forty".