42939409 has 2 divisors, whose sum is σ = 42939410. Its totient is φ = 42939408.

The previous prime is 42939389. The next prime is 42939427. The reversal of 42939409 is 90493924.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 41667025 + 1272384 = 6455^2 + 1128^2 .

It is a cyclic number.

It is not a de Polignac number, because 42939409 - 2¹¹ = 42937361 is a prime.

It is not a weakly prime, because it can be changed into another prime (42939439) 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, 21469704 + 21469705.

It is an arithmetic number, because the mean of its divisors is an integer number (21469705).

Almost surely, 2^42939409 is an apocalyptic number.

It is an amenable number.

42939409 is a deficient number, since it is larger than the sum of its proper divisors (1).

42939409 is an equidigital number, since it uses as much as digits as its factorization.

42939409 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 69984, while the sum is 40.

The square root of 42939409 is about 6552.8168752072. The cubic root of 42939409 is about 350.1751748954.

The spelling of 42939409 in words is "forty-two million, nine hundred thirty-nine thousand, four hundred nine".