21002223 has 16 divisors (see below), whose sum is σ = 30629376. Its totient is φ = 12695040.

The previous prime is 21002213. The next prime is 21002231. The reversal of 21002223 is 32220012.

It is not a de Polignac number, because 21002223 - 2⁴ = 21002207 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21002199 and 21002208.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21002203) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 18490 + ... + 19592.

It is an arithmetic number, because the mean of its divisors is an integer number (1914336).

Almost surely, 2^21002223 is an apocalyptic number.

21002223 is a deficient number, since it is larger than the sum of its proper divisors (9627153).

21002223 is a wasteful number, since it uses less digits than its factorization.

21002223 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1694.

The product of its (nonzero) digits is 48, while the sum is 12.

The square root of 21002223 is about 4582.8182377223. The cubic root of 21002223 is about 275.9021523556.

Adding to 21002223 its reverse (32220012), we get a palindrome (53222235).

It can be divided in two parts, 2100222 and 3, that added together give a triangular number (2100225 = T₂₀₄₉).

The spelling of 21002223 in words is "twenty-one million, two thousand, two hundred twenty-three".