29981209 has 4 divisors (see below), whose sum is σ = 30712500. Its totient is φ = 29249920.

The previous prime is 29981207. The next prime is 29981239. The reversal of 29981209 is 90218992.

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

It can be written as a sum of positive squares in 2 ways, for example, as 7209225 + 22771984 = 2685^2 + 4772^2 .

It is a cyclic number.

It is not a de Polignac number, because 29981209 - 2¹ = 29981207 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (29981207) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 365584 + ... + 365665.

It is an arithmetic number, because the mean of its divisors is an integer number (7678125).

Almost surely, 2^29981209 is an apocalyptic number.

It is an amenable number.

29981209 is a deficient number, since it is larger than the sum of its proper divisors (731291).

29981209 is an equidigital number, since it uses as much as digits as its factorization.

29981209 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 731290.

The product of its (nonzero) digits is 23328, while the sum is 40.

The square root of 29981209 is about 5475.5099305909. The cubic root of 29981209 is about 310.6583614831.

The spelling of 29981209 in words is "twenty-nine million, nine hundred eighty-one thousand, two hundred nine".