21205383 has 8 divisors (see below), whose sum is σ = 28461696. Its totient is φ = 14043000.

The previous prime is 21205381. The next prime is 21205391. The reversal of 21205383 is 38350212.

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

It is not a de Polignac number, because 21205383 - 2¹ = 21205381 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21205381) 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, 22953 + ... + 23858.

It is an arithmetic number, because the mean of its divisors is an integer number (3557712).

Almost surely, 2^21205383 is an apocalyptic number.

21205383 is a deficient number, since it is larger than the sum of its proper divisors (7256313).

21205383 is a wasteful number, since it uses less digits than its factorization.

21205383 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 46965.

The product of its (nonzero) digits is 1440, while the sum is 24.

The square root of 21205383 is about 4604.9302926320. The cubic root of 21205383 is about 276.7889237259.

Adding to 21205383 its reverse (38350212), we get a palindrome (59555595).

It can be divided in two parts, 2120 and 5383, that added together give a triangular number (7503 = T₁₂₂).

The spelling of 21205383 in words is "twenty-one million, two hundred five thousand, three hundred eighty-three".