21144234021 has 4 divisors (see below), whose sum is σ = 28192312032. Its totient is φ = 14096156012.

The previous prime is 21144234019. The next prime is 21144234031. The reversal of 21144234021 is 12043244112.

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 21144234021 - 2¹ = 21144234019 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21144233982 and 21144234000.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21144234031) 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, 3524039001 + ... + 3524039006.

It is an arithmetic number, because the mean of its divisors is an integer number (7048078008).

Almost surely, 2^21144234021 is an apocalyptic number.

It is an amenable number.

21144234021 is a deficient number, since it is larger than the sum of its proper divisors (7048078011).

21144234021 is an equidigital number, since it uses as much as digits as its factorization.

21144234021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7048078010.

The product of its (nonzero) digits is 1536, while the sum is 24.

Adding to 21144234021 its reverse (12043244112), we get a palindrome (33187478133).

The spelling of 21144234021 in words is "twenty-one billion, one hundred forty-four million, two hundred thirty-four thousand, twenty-one".