21310203 has 4 divisors (see below), whose sum is σ = 28413608. Its totient is φ = 14206800.

The previous prime is 21310199. The next prime is 21310207. The reversal of 21310203 is 30201312.

It is a happy number.

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

It is an interprime number because it is at equal distance from previous prime (21310199) and next prime (21310207).

It is not a de Polignac number, because 21310203 - 2² = 21310199 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21310207) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3551698 + ... + 3551703.

It is an arithmetic number, because the mean of its divisors is an integer number (7103402).

Almost surely, 2^21310203 is an apocalyptic number.

21310203 is a deficient number, since it is larger than the sum of its proper divisors (7103405).

21310203 is an equidigital number, since it uses as much as digits as its factorization.

21310203 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7103404.

The product of its (nonzero) digits is 36, while the sum is 12.

The square root of 21310203 is about 4616.2975424034. The cubic root of 21310203 is about 277.2442380084.

Adding to 21310203 its reverse (30201312), we get a palindrome (51511515).

The spelling of 21310203 in words is "twenty-one million, three hundred ten thousand, two hundred three".