21243310 has 32 divisors (see below), whose sum is σ = 41915232. Its totient is φ = 7687680.

The previous prime is 21243307. The next prime is 21243331. The reversal of 21243310 is 1334212.

It is a happy number.

It is a super-2 number, since 2×21243310² = 902556439512200, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 34122 + ... + 34738.

It is an arithmetic number, because the mean of its divisors is an integer number (1309851).

Almost surely, 2^21243310 is an apocalyptic number.

21243310 is a deficient number, since it is larger than the sum of its proper divisors (20671922).

21243310 is a wasteful number, since it uses less digits than its factorization.

21243310 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 948.

The product of its (nonzero) digits is 144, while the sum is 16.

The square root of 21243310 is about 4609.0465391445. The cubic root of 21243310 is about 276.9538428741.

Adding to 21243310 its reverse (1334212), we get a palindrome (22577522).

The spelling of 21243310 in words is "twenty-one million, two hundred forty-three thousand, three hundred ten".