209689450 has 12 divisors (see below), whose sum is σ = 390022470. Its totient is φ = 83875760.

The previous prime is 209689439. The next prime is 209689451. The reversal of 209689450 is 54986902.

It can be written as a sum of positive squares in 3 ways, for example, as 199911321 + 9778129 = 14139^2 + 3127^2 .

It is a junction number, because it is equal to n+sod(n) for n = 209689397 and 209689406.

It is not an unprimeable number, because it can be changed into a prime (209689451) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 2096845 + ... + 2096944.

Almost surely, 2^209689450 is an apocalyptic number.

209689450 is a deficient number, since it is larger than the sum of its proper divisors (180333020).

209689450 is a wasteful number, since it uses less digits than its factorization.

209689450 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4193801 (or 4193796 counting only the distinct ones).

The product of its (nonzero) digits is 155520, while the sum is 43.

The square root of 209689450 is about 14480.6577889266. The cubic root of 209689450 is about 594.0990531152.

The spelling of 209689450 in words is "two hundred nine million, six hundred eighty-nine thousand, four hundred fifty".