209005840 has 40 divisors (see below), whose sum is σ = 486540288. Its totient is φ = 83498880.

The previous prime is 209005831. The next prime is 209005861. The reversal of 209005840 is 48500902.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (40).

It is a junction number, because it is equal to n+sod(n) for n = 209005799 and 209005808.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 124849 + ... + 126511.

Almost surely, 2^209005840 is an apocalyptic number.

209005840 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

209005840 is an abundant number, since it is smaller than the sum of its proper divisors (277534448).

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

209005840 is a wasteful number, since it uses less digits than its factorization.

209005840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3247 (or 3241 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 28.

The square root of 209005840 is about 14457.0342740135. The cubic root of 209005840 is about 593.4527414713.

The spelling of 209005840 in words is "two hundred nine million, five thousand, eight hundred forty".