21440342 has 24 divisors (see below), whose sum is σ = 40814280. Its totient is φ = 8352960.

The previous prime is 21440317. The next prime is 21440351. The reversal of 21440342 is 24304412.

It is a congruent 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 11 ways as a sum of consecutive naturals, for example, 8867 + ... + 11022.

It is an arithmetic number, because the mean of its divisors is an integer number (1700595).

Almost surely, 2^21440342 is an apocalyptic number.

21440342 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

21440342 is a deficient number, since it is larger than the sum of its proper divisors (19373938).

21440342 is a wasteful number, since it uses less digits than its factorization.

21440342 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19916 (or 19909 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 20.

The square root of 21440342 is about 4630.3716913440. The cubic root of 21440342 is about 277.8074594535.

Adding to 21440342 its reverse (24304412), we get a palindrome (45744754).

The spelling of 21440342 in words is "twenty-one million, four hundred forty thousand, three hundred forty-two".