21223251236 has 24 divisors (see below), whose sum is σ = 40563180000. Its totient is φ = 9635964800.

The previous prime is 21223251191. The next prime is 21223251241. The reversal of 21223251236 is 63215232212.

It is a junction number, because it is equal to n+sod(n) for n = 21223251199 and 21223251208.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 234986 + ... + 312513.

It is an arithmetic number, because the mean of its divisors is an integer number (1690132500).

Almost surely, 2^21223251236 is an apocalyptic number.

It is an amenable number.

21223251236 is a deficient number, since it is larger than the sum of its proper divisors (19339928764).

21223251236 is a wasteful number, since it uses less digits than its factorization.

21223251236 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 548395 (or 548393 counting only the distinct ones).

The product of its digits is 8640, while the sum is 29.

Adding to 21223251236 its reverse (63215232212), we get a palindrome (84438483448).

The spelling of 21223251236 in words is "twenty-one billion, two hundred twenty-three million, two hundred fifty-one thousand, two hundred thirty-six".