21213124423 has 2 divisors, whose sum is σ = 21213124424. Its totient is φ = 21213124422.

The previous prime is 21213124417. The next prime is 21213124441. The reversal of 21213124423 is 32442131212.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21213124423 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21213124463) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10606562211 + 10606562212.

It is an arithmetic number, because the mean of its divisors is an integer number (10606562212).

Almost surely, 2^21213124423 is an apocalyptic number.

21213124423 is a deficient number, since it is larger than the sum of its proper divisors (1).

21213124423 is an equidigital number, since it uses as much as digits as its factorization.

21213124423 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2304, while the sum is 25.

Adding to 21213124423 its reverse (32442131212), we get a palindrome (53655255635).

The spelling of 21213124423 in words is "twenty-one billion, two hundred thirteen million, one hundred twenty-four thousand, four hundred twenty-three".