243121220554 has 4 divisors (see below), whose sum is σ = 364681830834. Its totient is φ = 121560610276.

The previous prime is 243121220491. The next prime is 243121220597. The reversal of 243121220554 is 455022121342.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 455022121342 = 2 ⋅227511060671.

It can be written as a sum of positive squares in only one way, i.e., 212645488225 + 30475732329 = 461135^2 + 174573^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 60780305137 + ... + 60780305140.

Almost surely, 2^243121220554 is an apocalyptic number.

243121220554 is a deficient number, since it is larger than the sum of its proper divisors (121560610280).

243121220554 is a wasteful number, since it uses less digits than its factorization.

243121220554 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 121560610279.

The product of its (nonzero) digits is 19200, while the sum is 31.

Adding to 243121220554 its reverse (455022121342), we get a palindrome (698143341896).

The spelling of 243121220554 in words is "two hundred forty-three billion, one hundred twenty-one million, two hundred twenty thousand, five hundred fifty-four".