209799040 has 128 divisors (see below), whose sum is σ = 579661920. Its totient is φ = 71761920.

The previous prime is 209799019. The next prime is 209799049. The reversal of 209799040 is 40997902.

It is a tau number, because it is divible by the number of its divisors (128).

It is a Harshad number since it is a multiple of its sum of digits (40).

It is a junction number, because it is equal to n+sod(n) for n = 209798984 and 209799002.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (209799049) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 118804 + ... + 120556.

Almost surely, 2^209799040 is an apocalyptic number.

209799040 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 209799040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (289830960).

209799040 is an abundant number, since it is smaller than the sum of its proper divisors (369862880).

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

209799040 is a wasteful number, since it uses less digits than its factorization.

209799040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1800 (or 1788 counting only the distinct ones).

The product of its (nonzero) digits is 40824, while the sum is 40.

The square root of 209799040 is about 14484.4413078310. The cubic root of 209799040 is about 594.2025330887.

The spelling of 209799040 in words is "two hundred nine million, seven hundred ninety-nine thousand, forty".