21440346 has 8 divisors (see below), whose sum is σ = 42880704. Its totient is φ = 7146780.

The previous prime is 21440317. The next prime is 21440351. The reversal of 21440346 is 64304412.

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

21440346 is an admirable number.

It is an unprimeable number.

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, 1786690 + ... + 1786701.

It is an arithmetic number, because the mean of its divisors is an integer number (5360088).

Almost surely, 2^21440346 is an apocalyptic number.

21440346 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

21440346 is a wasteful number, since it uses less digits than its factorization.

21440346 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3573396.

The product of its (nonzero) digits is 2304, while the sum is 24.

The square root of 21440346 is about 4630.3721232748. The cubic root of 21440346 is about 277.8074767298.

Adding to 21440346 its reverse (64304412), we get a palindrome (85744758).

The spelling of 21440346 in words is "twenty-one million, four hundred forty thousand, three hundred forty-six".