21344939 has 18 divisors (see below), whose sum is σ = 27223884. Its totient is φ = 16548840.

The previous prime is 21344933. The next prime is 21344951. The reversal of 21344939 is 93944312.

It is a de Polignac number, because none of the positive numbers 2^k-21344939 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21344899 and 21344908.

It is not an unprimeable number, because it can be changed into a prime (21344933) 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 17 ways as a sum of consecutive naturals, for example, 107162 + ... + 107360.

It is an arithmetic number, because the mean of its divisors is an integer number (1512438).

Almost surely, 2^21344939 is an apocalyptic number.

21344939 is a deficient number, since it is larger than the sum of its proper divisors (5878945).

21344939 is an equidigital number, since it uses as much as digits as its factorization.

21344939 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 423 (or 217 counting only the distinct ones).

The product of its digits is 23328, while the sum is 35.

The square root of 21344939 is about 4620.0583329651. The cubic root of 21344939 is about 277.3947938718.

The spelling of 21344939 in words is "twenty-one million, three hundred forty-four thousand, nine hundred thirty-nine".