213121404243 has 24 divisors (see below), whose sum is σ = 340428057840. Its totient is φ = 127395106560.

The previous prime is 213121404239. The next prime is 213121404257. The reversal of 213121404243 is 342404121312.

213121404243 is a `hidden beast` number, since 2 + 1 + 3 + 12 + 1 + 404 + 243 = 666.

213121404243 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 213121404243 - 2² = 213121404239 is a prime.

It is not an unprimeable number, because it can be changed into a prime (213121404233) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 14737578 + ... + 14752031.

It is an arithmetic number, because the mean of its divisors is an integer number (14184502410).

Almost surely, 2^213121404243 is an apocalyptic number.

213121404243 is a deficient number, since it is larger than the sum of its proper divisors (127306653597).

213121404243 is a wasteful number, since it uses less digits than its factorization.

213121404243 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29489699 (or 29489696 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 27.

Adding to 213121404243 its reverse (342404121312), we get a palindrome (555525525555).

The spelling of 213121404243 in words is "two hundred thirteen billion, one hundred twenty-one million, four hundred four thousand, two hundred forty-three".