209431040 has 320 divisors, whose sum is σ = 659957760. Its totient is φ = 61931520.

The previous prime is 209431021. The next prime is 209431073. The reversal of 209431040 is 40134902.

It is a tau number, because it is divible by the number of its divisors (320).

It is a super-2 number, since 2×209431040² = 87722721030963200, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 209430997 and 209431015.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 6755825 + ... + 6755855.

It is an arithmetic number, because the mean of its divisors is an integer number (2062368).

Almost surely, 2^209431040 is an apocalyptic number.

209431040 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 209431040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (329978880).

209431040 is an abundant number, since it is smaller than the sum of its proper divisors (450526720).

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

209431040 is a wasteful number, since it uses less digits than its factorization.

209431040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 103 (or 87 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 23.

The square root of 209431040 is about 14471.7324463936. The cubic root of 209431040 is about 593.8549075574.

Adding to 209431040 its reverse (40134902), we get a palindrome (249565942).

The spelling of 209431040 in words is "two hundred nine million, four hundred thirty-one thousand, forty".