21310223 has 12 divisors (see below), whose sum is σ = 23779752. Its totient is φ = 18939120.

The previous prime is 21310207. The next prime is 21310243. The reversal of 21310223 is 32201312.

It is a happy number.

It is not a de Polignac number, because 21310223 - 2⁴ = 21310207 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21310198 and 21310207.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21310243) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 23861 + ... + 24737.

It is an arithmetic number, because the mean of its divisors is an integer number (1981646).

Almost surely, 2^21310223 is an apocalyptic number.

21310223 is a deficient number, since it is larger than the sum of its proper divisors (2469529).

21310223 is an equidigital number, since it uses as much as digits as its factorization.

21310223 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 982 (or 935 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 14.

The square root of 21310223 is about 4616.2997086411. The cubic root of 21310223 is about 277.2443247413.

Adding to 21310223 its reverse (32201312), we get a palindrome (53511535).

The spelling of 21310223 in words is "twenty-one million, three hundred ten thousand, two hundred twenty-three".