209149769 has 4 divisors (see below), whose sum is σ = 216361860. Its totient is φ = 201937680.

The previous prime is 209149763. The next prime is 209149771. The reversal of 209149769 is 967941902.

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 42094144 + 167055625 = 6488^2 + 12925^2 .

It is a cyclic number.

It is not a de Polignac number, because 209149769 - 2¹⁶ = 209084233 is a prime.

It is a super-2 number, since 2×209149769² = 87487251745506722, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (209149763) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3606002 + ... + 3606059.

It is an arithmetic number, because the mean of its divisors is an integer number (54090465).

Almost surely, 2^209149769 is an apocalyptic number.

209149769 is a gapful number since it is divisible by the number (29) formed by its first and last digit.

It is an amenable number.

209149769 is a deficient number, since it is larger than the sum of its proper divisors (7212091).

209149769 is an equidigital number, since it uses as much as digits as its factorization.

209149769 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7212090.

The product of its (nonzero) digits is 244944, while the sum is 47.

The square root of 209149769 is about 14462.0112363392. The cubic root of 209149769 is about 593.5889345724.

The spelling of 209149769 in words is "two hundred nine million, one hundred forty-nine thousand, seven hundred sixty-nine".