21202423423 has 2 divisors, whose sum is σ = 21202423424. Its totient is φ = 21202423422.

The previous prime is 21202423391. The next prime is 21202423481. The reversal of 21202423423 is 32432420212.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21202423423 - 2⁵ = 21202423391 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21202426423) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10601211711 + 10601211712.

It is an arithmetic number, because the mean of its divisors is an integer number (10601211712).

Almost surely, 2^21202423423 is an apocalyptic number.

21202423423 is a deficient number, since it is larger than the sum of its proper divisors (1).

21202423423 is an equidigital number, since it uses as much as digits as its factorization.

21202423423 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4608, while the sum is 25.

Adding to 21202423423 its reverse (32432420212), we get a palindrome (53634843635).

The spelling of 21202423423 in words is "twenty-one billion, two hundred two million, four hundred twenty-three thousand, four hundred twenty-three".