42506021 has 4 divisors (see below), whose sum is σ = 44743200. Its totient is φ = 40268844.

The previous prime is 42506003. The next prime is 42506039. The reversal of 42506021 is 12060524.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is an interprime number because it is at equal distance from previous prime (42506003) and next prime (42506039).

It is a cyclic number.

It is not a de Polignac number, because 42506021 - 2¹⁰ = 42504997 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 42505984 and 42506002.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (42506041) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1118561 + ... + 1118598.

It is an arithmetic number, because the mean of its divisors is an integer number (11185800).

Almost surely, 2^42506021 is an apocalyptic number.

It is an amenable number.

42506021 is a deficient number, since it is larger than the sum of its proper divisors (2237179).

42506021 is a wasteful number, since it uses less digits than its factorization.

42506021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2237178.

The product of its (nonzero) digits is 480, while the sum is 20.

The square root of 42506021 is about 6519.6641784681. The cubic root of 42506021 is about 348.9930814741.

Adding to 42506021 its reverse (12060524), we get a palindrome (54566545).

The spelling of 42506021 in words is "forty-two million, five hundred six thousand, twenty-one".