209428079 has 4 divisors (see below), whose sum is σ = 239346384. Its totient is φ = 179509776.

The previous prime is 209428073. The next prime is 209428129. The reversal of 209428079 is 970824902.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-209428079 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (209428073) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 14959142 + ... + 14959155.

It is an arithmetic number, because the mean of its divisors is an integer number (59836596).

Almost surely, 2^209428079 is an apocalyptic number.

209428079 is a deficient number, since it is larger than the sum of its proper divisors (29918305).

209428079 is an equidigital number, since it uses as much as digits as its factorization.

209428079 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29918304.

The product of its (nonzero) digits is 72576, while the sum is 41.

The square root of 209428079 is about 14471.6301431456. The cubic root of 209428079 is about 593.8521088435.

The spelling of 209428079 in words is "two hundred nine million, four hundred twenty-eight thousand, seventy-nine".