3942409 has 2 divisors, whose sum is σ = 3942410. Its totient is φ = 3942408.

The previous prime is 3942403. The next prime is 3942413. The reversal of 3942409 is 9042493.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 2732409 + 1210000 = 1653^2 + 1100^2 .

It is an emirp because it is prime and its reverse (9042493) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 3942409 - 2³ = 3942401 is a prime.

It is not a weakly prime, because it can be changed into another prime (3942401) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1971204 + 1971205.

It is an arithmetic number, because the mean of its divisors is an integer number (1971205).

Almost surely, 2^3942409 is an apocalyptic number.

It is an amenable number.

3942409 is a deficient number, since it is larger than the sum of its proper divisors (1).

3942409 is an equidigital number, since it uses as much as digits as its factorization.

3942409 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 7776, while the sum is 31.

The square root of 3942409 is about 1985.5500497343. The cubic root of 3942409 is about 157.9745859888.

The spelling of 3942409 in words is "three million, nine hundred forty-two thousand, four hundred nine".