209470661 has 4 divisors (see below), whose sum is σ = 212421024. Its totient is φ = 206520300.

The previous prime is 209470621. The next prime is 209470663. The reversal of 209470661 is 166074902.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-209470661 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (209470663) 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, 1475075 + ... + 1475216.

It is an arithmetic number, because the mean of its divisors is an integer number (53105256).

Almost surely, 2^209470661 is an apocalyptic number.

It is an amenable number.

209470661 is a deficient number, since it is larger than the sum of its proper divisors (2950363).

209470661 is an equidigital number, since it uses as much as digits as its factorization.

209470661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2950362.

The product of its (nonzero) digits is 18144, while the sum is 35.

The square root of 209470661 is about 14473.1012917066. The cubic root of 209470661 is about 593.8923544765.

The spelling of 209470661 in words is "two hundred nine million, four hundred seventy thousand, six hundred sixty-one".