209965056 has 104 divisors (see below), whose sum is σ = 640077504. Its totient is φ = 59965440.

The previous prime is 209965051. The next prime is 209965061. The reversal of 209965056 is 650569902.

It is an interprime number because it is at equal distance from previous prime (209965051) and next prime (209965061).

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a junction number, because it is equal to n+sod(n) for n = 209964999 and 209965017.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (209965051) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 84796 + ... + 87236.

Almost surely, 2^209965056 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 209965056, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (320038752).

209965056 is an abundant number, since it is smaller than the sum of its proper divisors (430112448).

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

209965056 is an equidigital number, since it uses as much as digits as its factorization.

209965056 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2475 (or 2453 counting only the distinct ones).

The product of its (nonzero) digits is 145800, while the sum is 42.

The square root of 209965056 is about 14490.1710134836. The cubic root of 209965056 is about 594.3592244937.

The spelling of 209965056 in words is "two hundred nine million, nine hundred sixty-five thousand, fifty-six".