42109409 has 2 divisors, whose sum is σ = 42109410. Its totient is φ = 42109408.

The previous prime is 42109381. The next prime is 42109423. The reversal of 42109409 is 90490124.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 28121809 + 13987600 = 5303^2 + 3740^2 .

It is a cyclic number.

It is not a de Polignac number, because 42109409 - 2¹² = 42105313 is a prime.

It is not a weakly prime, because it can be changed into another prime (42109609) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21054704 + 21054705.

It is an arithmetic number, because the mean of its divisors is an integer number (21054705).

Almost surely, 2^42109409 is an apocalyptic number.

It is an amenable number.

42109409 is a deficient number, since it is larger than the sum of its proper divisors (1).

42109409 is an equidigital number, since it uses as much as digits as its factorization.

42109409 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2592, while the sum is 29.

The square root of 42109409 is about 6489.1762959562. The cubic root of 42109409 is about 347.9042350003.

The spelling of 42109409 in words is "forty-two million, one hundred nine thousand, four hundred nine".