21223355 has 8 divisors (see below), whose sum is σ = 25654752. Its totient is φ = 16854208.

The previous prime is 21223333. The next prime is 21223357. The reversal of 21223355 is 55332212.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21223355 - 2⁶ = 21223291 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21223355.

It is not an unprimeable number, because it can be changed into a prime (21223357) 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, 14807 + ... + 16176.

It is an arithmetic number, because the mean of its divisors is an integer number (3206844).

Almost surely, 2^21223355 is an apocalyptic number.

21223355 is a deficient number, since it is larger than the sum of its proper divisors (4431397).

21223355 is a wasteful number, since it uses less digits than its factorization.

21223355 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31125.

The product of its digits is 1800, while the sum is 23.

The square root of 21223355 is about 4606.8812661062. The cubic root of 21223355 is about 276.8670964220.

Adding to 21223355 its reverse (55332212), we get a palindrome (76555567).

The spelling of 21223355 in words is "twenty-one million, two hundred twenty-three thousand, three hundred fifty-five".