243121243440 has 160 divisors (see below), whose sum is σ = 758148278976. Its totient is φ = 64448593920.

The previous prime is 243121243397. The next prime is 243121243447. The reversal of 243121243440 is 44342121342.

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

It is a junction number, because it is equal to n+sod(n) for n = 243121243398 and 243121243407.

It is not an unprimeable number, because it can be changed into a prime (243121243447) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 35452492 + ... + 35459348.

Almost surely, 2^243121243440 is an apocalyptic number.

243121243440 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 243121243440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (379074139488).

243121243440 is an abundant number, since it is smaller than the sum of its proper divisors (515027035536).

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

243121243440 is a wasteful number, since it uses less digits than its factorization.

243121243440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7727 (or 7721 counting only the distinct ones).

The product of its (nonzero) digits is 18432, while the sum is 30.

Adding to 243121243440 its reverse (44342121342), we get a palindrome (287463364782).

The spelling of 243121243440 in words is "two hundred forty-three billion, one hundred twenty-one million, two hundred forty-three thousand, four hundred forty".