21213023423 has 16 divisors (see below), whose sum is σ = 22544421120. Its totient is φ = 19903395456.

The previous prime is 21213023417. The next prime is 21213023473. The reversal of 21213023423 is 32432031212.

It is a cyclic number.

It is not a de Polignac number, because 21213023423 - 2⁴ = 21213023407 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21213023473) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3576086 + ... + 3582012.

It is an arithmetic number, because the mean of its divisors is an integer number (1409026320).

Almost surely, 2^21213023423 is an apocalyptic number.

21213023423 is a deficient number, since it is larger than the sum of its proper divisors (1331397697).

21213023423 is a wasteful number, since it uses less digits than its factorization.

21213023423 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7726.

The product of its (nonzero) digits is 1728, while the sum is 23.

Adding to 21213023423 its reverse (32432031212), we get a palindrome (53645054635).

The spelling of 21213023423 in words is "twenty-one billion, two hundred thirteen million, twenty-three thousand, four hundred twenty-three".