42120409 has 2 divisors, whose sum is σ = 42120410. Its totient is φ = 42120408.

The previous prime is 42120391. The next prime is 42120427. The reversal of 42120409 is 90402124.

It is a balanced prime because it is at equal distance from previous prime (42120391) and next prime (42120427).

It can be written as a sum of positive squares in only one way, i.e., 34574400 + 7546009 = 5880^2 + 2747^2 .

It is a cyclic number.

It is not a de Polignac number, because 42120409 - 2¹¹ = 42118361 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 42120409.

It is not a weakly prime, because it can be changed into another prime (42120479) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21060204 + 21060205.

It is an arithmetic number, because the mean of its divisors is an integer number (21060205).

Almost surely, 2^42120409 is an apocalyptic number.

It is an amenable number.

42120409 is a deficient number, since it is larger than the sum of its proper divisors (1).

42120409 is an equidigital number, since it uses as much as digits as its factorization.

42120409 is an evil number, because the sum of its binary digits is even.

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

The square root of 42120409 is about 6490.0238058115. The cubic root of 42120409 is about 347.9345260405.

The spelling of 42120409 in words is "forty-two million, one hundred twenty thousand, four hundred nine".