42102409 has 2 divisors, whose sum is σ = 42102410. Its totient is φ = 42102408.

The previous prime is 42102373. The next prime is 42102419. The reversal of 42102409 is 90420124.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 41319184 + 783225 = 6428^2 + 885^2 .

It is a cyclic number.

It is not a de Polignac number, because 42102409 - 2¹¹ = 42100361 is a prime.

It is a super-2 number, since 2×42102409² = 3545225687206562, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 42102409.

It is not a weakly prime, because it can be changed into another prime (42102419) 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, 21051204 + 21051205.

It is an arithmetic number, because the mean of its divisors is an integer number (21051205).

Almost surely, 2^42102409 is an apocalyptic number.

It is an amenable number.

42102409 is a deficient number, since it is larger than the sum of its proper divisors (1).

42102409 is an equidigital number, since it uses as much as digits as its factorization.

42102409 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 576, while the sum is 22.

The square root of 42102409 is about 6488.6369138672. The cubic root of 42102409 is about 347.8849561371.

The spelling of 42102409 in words is "forty-two million, one hundred two thousand, four hundred nine".