21340312 has 16 divisors (see below), whose sum is σ = 45729360. Its totient is φ = 9145824.

The previous prime is 21340289. The next prime is 21340313. The reversal of 21340312 is 21304312.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21340313) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 190483 + ... + 190594.

It is an arithmetic number, because the mean of its divisors is an integer number (2858085).

Almost surely, 2^21340312 is an apocalyptic number.

It is an amenable number.

21340312 is an abundant number, since it is smaller than the sum of its proper divisors (24389048).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21340312 is a wasteful number, since it uses less digits than its factorization.

21340312 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 381090 (or 381086 counting only the distinct ones).

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

The square root of 21340312 is about 4619.5575545716. The cubic root of 21340312 is about 277.3747485508.

Adding to 21340312 its reverse (21304312), we get a palindrome (42644624).

The spelling of 21340312 in words is "twenty-one million, three hundred forty thousand, three hundred twelve".