21210423423 has 64 divisors (see below), whose sum is σ = 33751990272. Its totient is φ = 11597644800.

The previous prime is 21210423391. The next prime is 21210423427. The reversal of 21210423423 is 32432401212.

It is a happy number.

It is not a de Polignac number, because 21210423423 - 2⁵ = 21210423391 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21210423393 and 21210423402.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21210423427) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 9020698 + ... + 9023048.

It is an arithmetic number, because the mean of its divisors is an integer number (527374848).

Almost surely, 2^21210423423 is an apocalyptic number.

21210423423 is a deficient number, since it is larger than the sum of its proper divisors (12541566849).

21210423423 is a wasteful number, since it uses less digits than its factorization.

21210423423 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2604.

The product of its (nonzero) digits is 2304, while the sum is 24.

Adding to 21210423423 its reverse (32432401212), we get a palindrome (53642824635).

The spelling of 21210423423 in words is "twenty-one billion, two hundred ten million, four hundred twenty-three thousand, four hundred twenty-three".