42184781 has 2 divisors, whose sum is σ = 42184782. Its totient is φ = 42184780.

The previous prime is 42184759. The next prime is 42184819. The reversal of 42184781 is 18748124.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 25300900 + 16883881 = 5030^2 + 4109^2 .

It is a cyclic number.

It is not a de Polignac number, because 42184781 - 2¹⁴ = 42168397 is a prime.

It is a super-2 number, since 2×42184781² = 3559111496035922, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (42184711) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21092390 + 21092391.

It is an arithmetic number, because the mean of its divisors is an integer number (21092391).

Almost surely, 2^42184781 is an apocalyptic number.

It is an amenable number.

42184781 is a deficient number, since it is larger than the sum of its proper divisors (1).

42184781 is an equidigital number, since it uses as much as digits as its factorization.

42184781 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 14336, while the sum is 35.

The square root of 42184781 is about 6494.9812162931. The cubic root of 42184781 is about 348.1116835573. Note that the first 3 decimals are identical.

The spelling of 42184781 in words is "forty-two million, one hundred eighty-four thousand, seven hundred eighty-one".