209421900 has 216 divisors, whose sum is σ = 699788544. Its totient is φ = 52272000.

The previous prime is 209421881. The next prime is 209421907. The reversal of 209421900 is 9124902.

209421900 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a super-2 number, since 2×209421900² = 87715064399220000, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (209421907) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 1386825 + ... + 1386975.

Almost surely, 2^209421900 is an apocalyptic number.

209421900 is a gapful number since it is divisible by the number (20) 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 209421900, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (349894272).

209421900 is an abundant number, since it is smaller than the sum of its proper divisors (490366644).

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

209421900 is a wasteful number, since it uses less digits than its factorization.

209421900 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 261 (or 251 counting only the distinct ones).

The product of its (nonzero) digits is 1296, while the sum is 27.

The square root of 209421900 is about 14471.4166549098. The cubic root of 209421900 is about 593.8462684164.

The spelling of 209421900 in words is "two hundred nine million, four hundred twenty-one thousand, nine hundred".