21730203 has 24 divisors (see below), whose sum is σ = 34444800. Its totient is φ = 13091760.

The previous prime is 21730169. The next prime is 21730249. The reversal of 21730203 is 30203712.

It is not a de Polignac number, because 21730203 - 2⁶ = 21730139 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21730273) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 19150 + ... + 20252.

It is an arithmetic number, because the mean of its divisors is an integer number (1435200).

Almost surely, 2^21730203 is an apocalyptic number.

21730203 is a deficient number, since it is larger than the sum of its proper divisors (12714597).

21730203 is a wasteful number, since it uses less digits than its factorization.

21730203 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1319 (or 1316 counting only the distinct ones).

The product of its (nonzero) digits is 252, while the sum is 18.

The square root of 21730203 is about 4661.5665821696. The cubic root of 21730203 is about 279.0537916092.

Adding to 21730203 its reverse (30203712), we get a palindrome (51933915).

The spelling of 21730203 in words is "twenty-one million, seven hundred thirty thousand, two hundred three".