243978221 has 8 divisors (see below), whose sum is σ = 258669600. Its totient is φ = 229471920.

The previous prime is 243978211. The next prime is 243978233. The reversal of 243978221 is 122879342.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 243978221 - 2¹⁰ = 243977197 is a prime.

It is a super-3 number, since 3×243978221³ (a number of 26 digits) contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (243978211) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 43550 + ... + 48831.

It is an arithmetic number, because the mean of its divisors is an integer number (32333700).

Almost surely, 2^243978221 is an apocalyptic number.

It is an amenable number.

243978221 is a deficient number, since it is larger than the sum of its proper divisors (14691379).

243978221 is a wasteful number, since it uses less digits than its factorization.

243978221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 92539.

The product of its digits is 48384, while the sum is 38.

The square root of 243978221 is about 15619.8022074545. The cubic root of 243978221 is about 624.8613845128.

The spelling of 243978221 in words is "two hundred forty-three million, nine hundred seventy-eight thousand, two hundred twenty-one".