21149339 has 4 divisors (see below), whose sum is σ = 21167856. Its totient is φ = 21130824.

The previous prime is 21149333. The next prime is 21149353. The reversal of 21149339 is 93394112.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21149339 - 2⁸ = 21149083 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21149333) 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 3 ways as a sum of consecutive naturals, for example, 7424 + ... + 9869.

It is an arithmetic number, because the mean of its divisors is an integer number (5291964).

Almost surely, 2^21149339 is an apocalyptic number.

21149339 is a deficient number, since it is larger than the sum of its proper divisors (18517).

21149339 is a wasteful number, since it uses less digits than its factorization.

21149339 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18516.

The product of its digits is 5832, while the sum is 32.

The square root of 21149339 is about 4598.8410496559. The cubic root of 21149339 is about 276.5448654997.

The spelling of 21149339 in words is "twenty-one million, one hundred forty-nine thousand, three hundred thirty-nine".