21359939 has 8 divisors (see below), whose sum is σ = 23600160. Its totient is φ = 19229056.

The previous prime is 21359903. The next prime is 21359953. The reversal of 21359939 is 93995312.

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 21359939 - 2¹² = 21355843 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21359896 and 21359905.

It is not an unprimeable number, because it can be changed into a prime (21359959) 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 7 ways as a sum of consecutive naturals, for example, 26924 + ... + 27705.

It is an arithmetic number, because the mean of its divisors is an integer number (2950020).

Almost surely, 2^21359939 is an apocalyptic number.

21359939 is a deficient number, since it is larger than the sum of its proper divisors (2240221).

21359939 is a wasteful number, since it uses less digits than its factorization.

21359939 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 54669.

The product of its digits is 65610, while the sum is 41.

The square root of 21359939 is about 4621.6814039914. The cubic root of 21359939 is about 277.4597577118.

The spelling of 21359939 in words is "twenty-one million, three hundred fifty-nine thousand, nine hundred thirty-nine".