21232123216 has 40 divisors (see below), whose sum is σ = 44085999744. Its totient is φ = 9880041600.

The previous prime is 21232123207. The next prime is 21232123217. The reversal of 21232123216 is 61232123212.

It is an alternating number because its digits alternate between even and odd.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21232123217) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 766060 + ... + 793291.

Almost surely, 2^21232123216 is an apocalyptic number.

It is an amenable number.

21232123216 is an abundant number, since it is smaller than the sum of its proper divisors (22853876528).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21232123216 is a wasteful number, since it uses less digits than its factorization.

21232123216 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1559419 (or 1559413 counting only the distinct ones).

The product of its digits is 1728, while the sum is 25.

Adding to 21232123216 its reverse (61232123212), we get a palindrome (82464246428).

The spelling of 21232123216 in words is "twenty-one billion, two hundred thirty-two million, one hundred twenty-three thousand, two hundred sixteen".