42506521 has 4 divisors (see below), whose sum is σ = 42520192. Its totient is φ = 42492852.

The previous prime is 42506501. The next prime is 42506531. The reversal of 42506521 is 12560524.

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, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 42506521 - 2¹³ = 42498329 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (42506501) 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, 340 + ... + 9226.

It is an arithmetic number, because the mean of its divisors is an integer number (10630048).

Almost surely, 2^42506521 is an apocalyptic number.

It is an amenable number.

42506521 is a deficient number, since it is larger than the sum of its proper divisors (13671).

42506521 is an equidigital number, since it uses as much as digits as its factorization.

42506521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13670.

The product of its (nonzero) digits is 2400, while the sum is 25.

The square root of 42506521 is about 6519.7025238886. The cubic root of 42506521 is about 348.9944498752.

The spelling of 42506521 in words is "forty-two million, five hundred six thousand, five hundred twenty-one".