21100443243 has 16 divisors (see below), whose sum is σ = 30698990976. Its totient is φ = 12785048640.

The previous prime is 21100443233. The next prime is 21100443251. The reversal of 21100443243 is 34234400112.

It is not a de Polignac number, because 21100443243 - 2⁹ = 21100442731 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21100443233) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 64671 + ... + 215367.

It is an arithmetic number, because the mean of its divisors is an integer number (1918686936).

Almost surely, 2^21100443243 is an apocalyptic number.

21100443243 is a deficient number, since it is larger than the sum of its proper divisors (9598547733).

21100443243 is a wasteful number, since it uses less digits than its factorization.

21100443243 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 154954.

The product of its (nonzero) digits is 2304, while the sum is 24.

Adding to 21100443243 its reverse (34234400112), we get a palindrome (55334843355).

The spelling of 21100443243 in words is "twenty-one billion, one hundred million, four hundred forty-three thousand, two hundred forty-three".