21213124223 has 4 divisors (see below), whose sum is σ = 21213902640. Its totient is φ = 21212345808.

The previous prime is 21213124171. The next prime is 21213124277. The reversal of 21213124223 is 32242131212.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21213124223 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21213124423) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 346790 + ... + 403347.

It is an arithmetic number, because the mean of its divisors is an integer number (5303475660).

Almost surely, 2^21213124223 is an apocalyptic number.

21213124223 is a deficient number, since it is larger than the sum of its proper divisors (778417).

21213124223 is an equidigital number, since it uses as much as digits as its factorization.

21213124223 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 778416.

The product of its digits is 1152, while the sum is 23.

Adding to 21213124223 its reverse (32242131212), we get a palindrome (53455255435).

The spelling of 21213124223 in words is "twenty-one billion, two hundred thirteen million, one hundred twenty-four thousand, two hundred twenty-three".