21144021823 has 2 divisors, whose sum is σ = 21144021824. Its totient is φ = 21144021822.

The previous prime is 21144021763. The next prime is 21144021859. The reversal of 21144021823 is 32812044112.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21144021823 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21144021791 and 21144021800.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21144021523) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10572010911 + 10572010912.

It is an arithmetic number, because the mean of its divisors is an integer number (10572010912).

Almost surely, 2^21144021823 is an apocalyptic number.

21144021823 is a deficient number, since it is larger than the sum of its proper divisors (1).

21144021823 is an equidigital number, since it uses as much as digits as its factorization.

21144021823 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3072, while the sum is 28.

Adding to 21144021823 its reverse (32812044112), we get a palindrome (53956065935).

The spelling of 21144021823 in words is "twenty-one billion, one hundred forty-four million, twenty-one thousand, eight hundred twenty-three".