21111221243 has 8 divisors (see below), whose sum is σ = 24141631488. Its totient is φ = 18084441384.

The previous prime is 21111221227. The next prime is 21111221249. The reversal of 21111221243 is 34212211112.

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 21111221243 - 2⁴ = 21111221227 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21111221249) 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, 895121 + ... + 918402.

It is an arithmetic number, because the mean of its divisors is an integer number (3017703936).

Almost surely, 2^21111221243 is an apocalyptic number.

21111221243 is a deficient number, since it is larger than the sum of its proper divisors (3030410245).

21111221243 is a wasteful number, since it uses less digits than its factorization.

21111221243 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1815193.

The product of its digits is 192, while the sum is 20.

Adding to 21111221243 its reverse (34212211112), we get a palindrome (55323432355).

The spelling of 21111221243 in words is "twenty-one billion, one hundred eleven million, two hundred twenty-one thousand, two hundred forty-three".