209780928 has 336 divisors, whose sum is σ = 745565184. Its totient is φ = 57231360.

The previous prime is 209780899. The next prime is 209780929. The reversal of 209780928 is 829087902.

209780928 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a tau number, because it is divible by the number of its divisors (336).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (209780929) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 4463401 + ... + 4463447.

It is an arithmetic number, because the mean of its divisors is an integer number (2218944).

Almost surely, 2^209780928 is an apocalyptic number.

209780928 is a gapful number since it is divisible by the number (28) 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 209780928, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (372782592).

209780928 is an abundant number, since it is smaller than the sum of its proper divisors (535784256).

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

209780928 is an equidigital number, since it uses as much as digits as its factorization.

209780928 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 122 (or 100 counting only the distinct ones).

The product of its (nonzero) digits is 145152, while the sum is 45.

The square root of 209780928 is about 14483.8160717402. The cubic root of 209780928 is about 594.1854333823.

The spelling of 209780928 in words is "two hundred nine million, seven hundred eighty thousand, nine hundred twenty-eight".