21243394 has 8 divisors (see below), whose sum is σ = 31898880. Its totient is φ = 10610436.

The previous prime is 21243361. The next prime is 21243403. The reversal of 21243394 is 49334212.

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

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3034 + ... + 7189.

It is an arithmetic number, because the mean of its divisors is an integer number (3987360).

Almost surely, 2^21243394 is an apocalyptic number.

21243394 is a deficient number, since it is larger than the sum of its proper divisors (10655486).

21243394 is a wasteful number, since it uses less digits than its factorization.

21243394 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11264.

The product of its digits is 5184, while the sum is 28.

The square root of 21243394 is about 4609.0556516493. The cubic root of 21243394 is about 276.9542079160.

The spelling of 21243394 in words is "twenty-one million, two hundred forty-three thousand, three hundred ninety-four".