84581561 has 2 divisors, whose sum is σ = 84581562. Its totient is φ = 84581560.

The previous prime is 84581551. The next prime is 84581569. The reversal of 84581561 is 16518548.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 82810000 + 1771561 = 9100^2 + 1331^2 .

It is a cyclic number.

It is not a de Polignac number, because 84581561 - 2¹⁴ = 84565177 is a prime.

It is a super-2 number, since 2×84581561² = 14308080922393442, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (84581569) 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 as a sum of consecutive naturals, namely, 42290780 + 42290781.

It is an arithmetic number, because the mean of its divisors is an integer number (42290781).

Almost surely, 2^84581561 is an apocalyptic number.

It is an amenable number.

84581561 is a deficient number, since it is larger than the sum of its proper divisors (1).

84581561 is an equidigital number, since it uses as much as digits as its factorization.

84581561 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 38400, while the sum is 38.

The square root of 84581561 is about 9196.8234189855. The cubic root of 84581561 is about 438.9602878826.

The spelling of 84581561 in words is "eighty-four million, five hundred eighty-one thousand, five hundred sixty-one".