42805561 has 2 divisors, whose sum is σ = 42805562. Its totient is φ = 42805560.

The previous prime is 42805487. The next prime is 42805589. The reversal of 42805561 is 16550824.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 34574400 + 8231161 = 5880^2 + 2869^2 .

It is a cyclic number.

It is not a de Polignac number, because 42805561 - 2¹³ = 42797369 is a prime.

It is not a weakly prime, because it can be changed into another prime (42805361) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21402780 + 21402781.

It is an arithmetic number, because the mean of its divisors is an integer number (21402781).

Almost surely, 2^42805561 is an apocalyptic number.

It is an amenable number.

42805561 is a deficient number, since it is larger than the sum of its proper divisors (1).

42805561 is an equidigital number, since it uses as much as digits as its factorization.

42805561 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 9600, while the sum is 31.

The square root of 42805561 is about 6542.5958915403. The cubic root of 42805561 is about 349.8109482426.

The spelling of 42805561 in words is "forty-two million, eight hundred five thousand, five hundred sixty-one".