42506561 has 4 divisors (see below), whose sum is σ = 42566400. Its totient is φ = 42446724.

The previous prime is 42506539. The next prime is 42506587. The reversal of 42506561 is 16560524.

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 a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-42506561 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, 28841 + ... + 30278.

It is an arithmetic number, because the mean of its divisors is an integer number (10641600).

Almost surely, 2^42506561 is an apocalyptic number.

It is an amenable number.

42506561 is a deficient number, since it is larger than the sum of its proper divisors (59839).

42506561 is an equidigital number, since it uses as much as digits as its factorization.

42506561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 59838.

The product of its (nonzero) digits is 7200, while the sum is 29.

The square root of 42506561 is about 6519.7055915125. The cubic root of 42506561 is about 348.9945593468.

The spelling of 42506561 in words is "forty-two million, five hundred six thousand, five hundred sixty-one".