42239521 has 4 divisors (see below), whose sum is σ = 42254100. Its totient is φ = 42224944.

The previous prime is 42239503. The next prime is 42239539. The reversal of 42239521 is 12593224.

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

It is an interprime number because it is at equal distance from previous prime (42239503) and next prime (42239539).

It can be written as a sum of positive squares in 2 ways, for example, as 12110400 + 30129121 = 3480^2 + 5489^2 .

It is a cyclic number.

It is not a de Polignac number, because 42239521 - 2¹⁷ = 42108449 is a prime.

It is a Duffinian number.

It is a plaindrome in base 13.

It is a self number, because there is not a number n which added to its sum of digits gives 42239521.

It is not an unprimeable number, because it can be changed into a prime (42239551) 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, 1306 + ... + 9283.

It is an arithmetic number, because the mean of its divisors is an integer number (10563525).

Almost surely, 2^42239521 is an apocalyptic number.

It is an amenable number.

42239521 is a deficient number, since it is larger than the sum of its proper divisors (14579).

42239521 is a wasteful number, since it uses less digits than its factorization.

42239521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14578.

The product of its digits is 4320, while the sum is 28.

The square root of 42239521 is about 6499.1938730892. The cubic root of 42239521 is about 348.2621912103.

The spelling of 42239521 in words is "forty-two million, two hundred thirty-nine thousand, five hundred twenty-one".