42009399 has 24 divisors (see below), whose sum is σ = 65245440. Its totient is φ = 25962768.

The previous prime is 42009391. The next prime is 42009403. The reversal of 42009399 is 99390024.

It is not a de Polignac number, because 42009399 - 2³ = 42009391 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (42009391) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 5424 + ... + 10650.

It is an arithmetic number, because the mean of its divisors is an integer number (2718560).

Almost surely, 2^42009399 is an apocalyptic number.

42009399 is a deficient number, since it is larger than the sum of its proper divisors (23236041).

42009399 is a wasteful number, since it uses less digits than its factorization.

42009399 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5299 (or 5296 counting only the distinct ones).

The product of its (nonzero) digits is 17496, while the sum is 36.

The square root of 42009399 is about 6481.4658064361. The cubic root of 42009399 is about 347.6285920582.

Subtracting 42009399 from its reverse (99390024), we obtain a square (57380625 = 7575²).

The spelling of 42009399 in words is "forty-two million, nine thousand, three hundred ninety-nine".