21124410621 has 4 divisors (see below), whose sum is σ = 28165880832. Its totient is φ = 14082940412.

The previous prime is 21124410617. The next prime is 21124410623. The reversal of 21124410621 is 12601442112.

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 a cyclic number.

It is not a de Polignac number, because 21124410621 - 2² = 21124410617 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21124410591 and 21124410600.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21124410623) 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, 3520735101 + ... + 3520735106.

It is an arithmetic number, because the mean of its divisors is an integer number (7041470208).

Almost surely, 2^21124410621 is an apocalyptic number.

It is an amenable number.

21124410621 is a deficient number, since it is larger than the sum of its proper divisors (7041470211).

21124410621 is an equidigital number, since it uses as much as digits as its factorization.

21124410621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7041470210.

The product of its (nonzero) digits is 768, while the sum is 24.

Adding to 21124410621 its reverse (12601442112), we get a palindrome (33725852733).

The spelling of 21124410621 in words is "twenty-one billion, one hundred twenty-four million, four hundred ten thousand, six hundred twenty-one".