209604864 has 144 divisors (see below), whose sum is σ = 644661248. Its totient is φ = 59222016.

The previous prime is 209604859. The next prime is 209604869. The reversal of 209604864 is 468406902.

It is an interprime number because it is at equal distance from previous prime (209604859) and next prime (209604869).

It is not an unprimeable number, because it can be changed into a prime (209604869) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 682599 + ... + 682905.

Almost surely, 2^209604864 is an apocalyptic number.

209604864 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 209604864, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (322330624).

209604864 is an abundant number, since it is smaller than the sum of its proper divisors (435056384).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

209604864 is a wasteful number, since it uses less digits than its factorization.

209604864 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 460 (or 446 counting only the distinct ones).

The product of its (nonzero) digits is 82944, while the sum is 39.

The square root of 209604864 is about 14477.7368397136. The cubic root of 209604864 is about 594.0191584248.

The spelling of 209604864 in words is "two hundred nine million, six hundred four thousand, eight hundred sixty-four".