21123454140243 has 48 divisors (see below), whose sum is σ = 38113297121536. Its totient is φ = 10975742585280.

The previous prime is 21123454140241. The next prime is 21123454140253. The reversal of 21123454140243 is 34204145432112.

21123454140243 is a `hidden beast` number, since 2 + 1 + 1 + 2 + 34 + 541 + 40 + 2 + 43 = 666.

It is not a de Polignac number, because 21123454140243 - 2¹ = 21123454140241 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21123454140198 and 21123454140207.

It is not an unprimeable number, because it can be changed into a prime (21123454140241) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 192420973 + ... + 192530718.

Almost surely, 2^{21123454140243} is an apocalyptic number.

21123454140243 is a deficient number, since it is larger than the sum of its proper divisors (16989842981293).

21123454140243 is a wasteful number, since it uses less digits than its factorization.

21123454140243 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 384951784 (or 384951781 counting only the distinct ones).

The product of its (nonzero) digits is 92160, while the sum is 36.

Adding to 21123454140243 its reverse (34204145432112), we get a palindrome (55327599572355).

The spelling of 21123454140243 in words is "twenty-one trillion, one hundred twenty-three billion, four hundred fifty-four million, one hundred forty thousand, two hundred forty-three".