209213928 has 240 divisors, whose sum is σ = 744876000. Its totient is φ = 54250560.

The previous prime is 209213891. The next prime is 209213971. The reversal of 209213928 is 829312902.

209213928 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 209213892 and 209213901.

It is an unprimeable number.

It is a polite number, since it can be written in 59 ways as a sum of consecutive naturals, for example, 348973 + ... + 349571.

It is an arithmetic number, because the mean of its divisors is an integer number (3103650).

Almost surely, 2^209213928 is an apocalyptic number.

209213928 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 209213928, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (372438000).

209213928 is an abundant number, since it is smaller than the sum of its proper divisors (535662072).

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

209213928 is a wasteful number, since it uses less digits than its factorization.

209213928 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 642 (or 622 counting only the distinct ones).

The product of its (nonzero) digits is 15552, while the sum is 36.

The square root of 209213928 is about 14464.2292570327. The cubic root of 209213928 is about 593.6496250194.

The spelling of 209213928 in words is "two hundred nine million, two hundred thirteen thousand, nine hundred twenty-eight".