243209820 has 192 divisors, whose sum is σ = 860461056. Its totient is φ = 50012160.

The previous prime is 243209773. The next prime is 243209831. The reversal of 243209820 is 28902342.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 163480 + ... + 164960.

It is an arithmetic number, because the mean of its divisors is an integer number (4481568).

Almost surely, 2^243209820 is an apocalyptic number.

243209820 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 243209820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (430230528).

243209820 is an abundant number, since it is smaller than the sum of its proper divisors (617251236).

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

243209820 is a wasteful number, since it uses less digits than its factorization.

243209820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1540 (or 1538 counting only the distinct ones).

The product of its (nonzero) digits is 6912, while the sum is 30.

The square root of 243209820 is about 15595.1857956230. The cubic root of 243209820 is about 624.2047014964.

The spelling of 243209820 in words is "two hundred forty-three million, two hundred nine thousand, eight hundred twenty".