84020561 has 2 divisors, whose sum is σ = 84020562. Its totient is φ = 84020560.

The previous prime is 84020557. The next prime is 84020567. The reversal of 84020561 is 16502048.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 81360400 + 2660161 = 9020^2 + 1631^2 .

It is a cyclic number.

It is not a de Polignac number, because 84020561 - 2² = 84020557 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 84020561.

It is not a weakly prime, because it can be changed into another prime (84020567) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 42010280 + 42010281.

It is an arithmetic number, because the mean of its divisors is an integer number (42010281).

Almost surely, 2^84020561 is an apocalyptic number.

It is an amenable number.

84020561 is a deficient number, since it is larger than the sum of its proper divisors (1).

84020561 is an equidigital number, since it uses as much as digits as its factorization.

84020561 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1920, while the sum is 26.

The square root of 84020561 is about 9166.2730157900. The cubic root of 84020561 is about 437.9876441265.

The spelling of 84020561 in words is "eighty-four million, twenty thousand, five hundred sixty-one".