21203385 has 16 divisors (see below), whose sum is σ = 38772096. Its totient is φ = 9692928.

The previous prime is 21203383. The next prime is 21203407. The reversal of 21203385 is 58330212.

It is not a de Polignac number, because 21203385 - 2¹ = 21203383 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21203383) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 100864 + ... + 101073.

It is an arithmetic number, because the mean of its divisors is an integer number (2423256).

Almost surely, 2^21203385 is an apocalyptic number.

It is an amenable number.

21203385 is a deficient number, since it is larger than the sum of its proper divisors (17568711).

21203385 is a wasteful number, since it uses less digits than its factorization.

21203385 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 201952.

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

The square root of 21203385 is about 4604.7133461270. The cubic root of 21203385 is about 276.7802303101.

Adding to 21203385 its reverse (58330212), we get a palindrome (79533597).

The spelling of 21203385 in words is "twenty-one million, two hundred three thousand, three hundred eighty-five".