21211703 has 4 divisors (see below), whose sum is σ = 21334488. Its totient is φ = 21088920.

The previous prime is 21211643. The next prime is 21211709. The reversal of 21211703 is 30711212.

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 21211703 - 2¹² = 21207607 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21211709) 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, 61133 + ... + 61478.

It is an arithmetic number, because the mean of its divisors is an integer number (5333622).

Almost surely, 2^21211703 is an apocalyptic number.

21211703 is a deficient number, since it is larger than the sum of its proper divisors (122785).

21211703 is a wasteful number, since it uses less digits than its factorization.

21211703 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 122784.

The product of its (nonzero) digits is 84, while the sum is 17.

The square root of 21211703 is about 4605.6164625379. The cubic root of 21211703 is about 276.8164188238.

Adding to 21211703 its reverse (30711212), we get a palindrome (51922915).

The spelling of 21211703 in words is "twenty-one million, two hundred eleven thousand, seven hundred three".