21404024423 has 2 divisors, whose sum is σ = 21404024424. Its totient is φ = 21404024422.

The previous prime is 21404024413. The next prime is 21404024429. The reversal of 21404024423 is 32442040412.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21404024423 - 2¹² = 21404020327 is a prime.

It is a Sophie Germain prime.

It is a junction number, because it is equal to n+sod(n) for n = 21404024392 and 21404024401.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21404024429) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10702012211 + 10702012212.

It is an arithmetic number, because the mean of its divisors is an integer number (10702012212).

Almost surely, 2^21404024423 is an apocalyptic number.

21404024423 is a deficient number, since it is larger than the sum of its proper divisors (1).

21404024423 is an equidigital number, since it uses as much as digits as its factorization.

21404024423 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 6144, while the sum is 26.

Adding to 21404024423 its reverse (32442040412), we get a palindrome (53846064835).

The spelling of 21404024423 in words is "twenty-one billion, four hundred four million, twenty-four thousand, four hundred twenty-three".