42820561 has 12 divisors (see below), whose sum is σ = 50972592. Its totient is φ = 35848008.

The previous prime is 42820537. The next prime is 42820567. The reversal of 42820561 is 16502824.

42820561 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 42820561 - 2⁹ = 42820049 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (42820567) by changing a digit.

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 11 ways as a sum of consecutive naturals, for example, 8055 + ... + 12268.

It is an arithmetic number, because the mean of its divisors is an integer number (4247716).

Almost surely, 2^42820561 is an apocalyptic number.

It is an amenable number.

42820561 is a deficient number, since it is larger than the sum of its proper divisors (8152031).

42820561 is a wasteful number, since it uses less digits than its factorization.

42820561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20380 (or 20373 counting only the distinct ones).

The product of its (nonzero) digits is 3840, while the sum is 28.

The square root of 42820561 is about 6543.7421251147. The cubic root of 42820561 is about 349.8518039267.

The spelling of 42820561 in words is "forty-two million, eight hundred twenty thousand, five hundred sixty-one".