21312442 has 8 divisors (see below), whose sum is σ = 32180832. Its totient is φ = 10585500.

The previous prime is 21312439. The next prime is 21312449. The reversal of 21312442 is 24421312.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not an unprimeable number, because it can be changed into a prime (21312449) 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 3 ways as a sum of consecutive naturals, for example, 34984 + ... + 35587.

It is an arithmetic number, because the mean of its divisors is an integer number (4022604).

Almost surely, 2^21312442 is an apocalyptic number.

21312442 is a deficient number, since it is larger than the sum of its proper divisors (10868390).

21312442 is a wasteful number, since it uses less digits than its factorization.

21312442 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 70724.

The product of its digits is 384, while the sum is 19.

The square root of 21312442 is about 4616.5400463984. The cubic root of 21312442 is about 277.2539474124.

Adding to 21312442 its reverse (24421312), we get a palindrome (45733754).

The spelling of 21312442 in words is "twenty-one million, three hundred twelve thousand, four hundred forty-two".