42009523 has 4 divisors (see below), whose sum is σ = 43836048. Its totient is φ = 40183000.

The previous prime is 42009509. The next prime is 42009571. The reversal of 42009523 is 32590024.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 42009523 - 2⁵ = 42009491 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (42009823) 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, 913228 + ... + 913273.

It is an arithmetic number, because the mean of its divisors is an integer number (10959012).

Almost surely, 2^42009523 is an apocalyptic number.

42009523 is a deficient number, since it is larger than the sum of its proper divisors (1826525).

42009523 is a wasteful number, since it uses less digits than its factorization.

42009523 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1826524.

The product of its (nonzero) digits is 2160, while the sum is 25.

The square root of 42009523 is about 6481.4753721664. The cubic root of 42009523 is about 347.6289340920.

Adding to 42009523 its reverse (32590024), we get a palindrome (74599547).

The spelling of 42009523 in words is "forty-two million, nine thousand, five hundred twenty-three".