243393840 has 120 divisors (see below), whose sum is σ = 825737328. Its totient is φ = 64243200.

The previous prime is 243393827. The next prime is 243393847. The reversal of 243393840 is 48393342.

It is a happy number.

243393840 is a `hidden beast` number, since 243 + 39 + 384 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (120).

It is a super-2 number, since 2×243393840² = 118481122699891200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 243393795 and 243393804.

It is not an unprimeable number, because it can be changed into a prime (243393847) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 71047 + ... + 74393.

Almost surely, 2^243393840 is an apocalyptic number.

243393840 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 243393840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (412868664).

243393840 is an abundant number, since it is smaller than the sum of its proper divisors (582343488).

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

243393840 is a wasteful number, since it uses less digits than its factorization.

243393840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3467 (or 3458 counting only the distinct ones).

The product of its (nonzero) digits is 62208, while the sum is 36.

The square root of 243393840 is about 15601.0845776824. The cubic root of 243393840 is about 624.3620926068.

The spelling of 243393840 in words is "two hundred forty-three million, three hundred ninety-three thousand, eight hundred forty".