42521405 has 16 divisors (see below), whose sum is σ = 52301424. Its totient is φ = 33177600.

The previous prime is 42521389. The next prime is 42521419. The reversal of 42521405 is 50412524.

It is a happy number.

42521405 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 8 ways, for example, as 7546009 + 34975396 = 2747^2 + 5914^2 .

It is not a de Polignac number, because 42521405 - 2⁴ = 42521389 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 34805 + ... + 36005.

It is an arithmetic number, because the mean of its divisors is an integer number (3268839).

Almost surely, 2^42521405 is an apocalyptic number.

It is an amenable number.

42521405 is a deficient number, since it is larger than the sum of its proper divisors (9780019).

42521405 is a wasteful number, since it uses less digits than its factorization.

42521405 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1376.

The product of its (nonzero) digits is 1600, while the sum is 23.

The square root of 42521405 is about 6520.8438871054. The cubic root of 42521405 is about 349.0351795256.

Adding to 42521405 its reverse (50412524), we get a palindrome (92933929).

The spelling of 42521405 in words is "forty-two million, five hundred twenty-one thousand, four hundred five".