21223939 has 8 divisors (see below), whose sum is σ = 24515568. Its totient is φ = 18159360.

The previous prime is 21223927. The next prime is 21223957. The reversal of 21223939 is 93932212.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 21223939 - 2⁹ = 21223427 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21223939.

It is not an unprimeable number, because it can be changed into a prime (21223739) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 56562 + ... + 56935.

It is an arithmetic number, because the mean of its divisors is an integer number (3064446).

Almost surely, 2^21223939 is an apocalyptic number.

21223939 is a deficient number, since it is larger than the sum of its proper divisors (3291629).

21223939 is a wasteful number, since it uses less digits than its factorization.

21223939 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 113525.

The product of its digits is 5832, while the sum is 31.

The square root of 21223939 is about 4606.9446491140. The cubic root of 21223939 is about 276.8696359027.

The spelling of 21223939 in words is "twenty-one million, two hundred twenty-three thousand, nine hundred thirty-nine".