21818312 has 32 divisors (see below), whose sum is σ = 41817600. Its totient is φ = 10670400.

The previous prime is 21818311. The next prime is 21818339. The reversal of 21818312 is 21381812.

It is not an unprimeable number, because it can be changed into a prime (21818311) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 114137 + ... + 114327.

It is an arithmetic number, because the mean of its divisors is an integer number (1306800).

Almost surely, 2^21818312 is an apocalyptic number.

It is an amenable number.

21818312 is a deficient number, since it is larger than the sum of its proper divisors (19999288).

21818312 is a wasteful number, since it uses less digits than its factorization.

21818312 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 437 (or 433 counting only the distinct ones).

The product of its digits is 768, while the sum is 26.

The square root of 21818312 is about 4671.0076000795. The cubic root of 21818312 is about 279.4304408621.

The spelling of 21818312 in words is "twenty-one million, eight hundred eighteen thousand, three hundred twelve".