21101223 has 32 divisors (see below), whose sum is σ = 33449472. Its totient is φ = 11664000.

The previous prime is 21101219. The next prime is 21101243. The reversal of 21101223 is 32210112.

It is not a de Polignac number, because 21101223 - 2² = 21101219 is a prime.

It is a super-2 number, since 2×21101223² = 890523224191458, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21101199 and 21101208.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21101243) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 43086 + ... + 43572.

It is an arithmetic number, because the mean of its divisors is an integer number (1045296).

Almost surely, 2^21101223 is an apocalyptic number.

21101223 is a deficient number, since it is larger than the sum of its proper divisors (12348249).

21101223 is a wasteful number, since it uses less digits than its factorization.

21101223 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 615.

The product of its (nonzero) digits is 24, while the sum is 12.

The square root of 21101223 is about 4593.6067528686. The cubic root of 21101223 is about 276.3349876032.

Adding to 21101223 its reverse (32210112), we get a palindrome (53311335).

Subtracting 21101223 from its reverse (32210112), we obtain a square (11108889 = 3333²).

It can be divided in two parts, 2110 and 1223, that added together give a palindrome (3333).

The spelling of 21101223 in words is "twenty-one million, one hundred one thousand, two hundred twenty-three".