21124043121 has 4 divisors (see below), whose sum is σ = 28165390832. Its totient is φ = 14082695412.

The previous prime is 21124043119. The next prime is 21124043123. The reversal of 21124043121 is 12134042112.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is an interprime number because it is at equal distance from previous prime (21124043119) and next prime (21124043123).

It is not a de Polignac number, because 21124043121 - 2¹ = 21124043119 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21124043123) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3520673851 + ... + 3520673856.

It is an arithmetic number, because the mean of its divisors is an integer number (7041347708).

Almost surely, 2^21124043121 is an apocalyptic number.

It is an amenable number.

21124043121 is a deficient number, since it is larger than the sum of its proper divisors (7041347711).

21124043121 is an equidigital number, since it uses as much as digits as its factorization.

21124043121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7041347710.

The product of its (nonzero) digits is 384, while the sum is 21.

Adding to 21124043121 its reverse (12134042112), we get a palindrome (33258085233).

The spelling of 21124043121 in words is "twenty-one billion, one hundred twenty-four million, forty-three thousand, one hundred twenty-one".