209986540 has 12 divisors (see below), whose sum is σ = 440971776. Its totient is φ = 83994608.

The previous prime is 209986519. The next prime is 209986549. The reversal of 209986540 is 45689902.

It is not an unprimeable number, because it can be changed into a prime (209986549) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5249644 + ... + 5249683.

It is an arithmetic number, because the mean of its divisors is an integer number (36747648).

Almost surely, 2^209986540 is an apocalyptic number.

209986540 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

209986540 is an abundant number, since it is smaller than the sum of its proper divisors (230985236).

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

209986540 is a wasteful number, since it uses less digits than its factorization.

209986540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10499336 (or 10499334 counting only the distinct ones).

The product of its (nonzero) digits is 155520, while the sum is 43.

The square root of 209986540 is about 14490.9123246261. The cubic root of 209986540 is about 594.3794957686.

The spelling of 209986540 in words is "two hundred nine million, nine hundred eighty-six thousand, five hundred forty".