21311212303 has 4 divisors (see below), whose sum is σ = 21764642400. Its totient is φ = 20857782208.

The previous prime is 21311212301. The next prime is 21311212313. The reversal of 21311212303 is 30321211312.

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 21311212303 - 2¹ = 21311212301 is a prime.

It is a super-4 number, since 4×21311212303⁴ (a number of 42 digits) contains 4444 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21311212301) 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, 226714978 + ... + 226715071.

It is an arithmetic number, because the mean of its divisors is an integer number (5441160600).

Almost surely, 2^21311212303 is an apocalyptic number.

21311212303 is a deficient number, since it is larger than the sum of its proper divisors (453430097).

21311212303 is an equidigital number, since it uses as much as digits as its factorization.

21311212303 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 453430096.

The product of its (nonzero) digits is 216, while the sum is 19.

Adding to 21311212303 its reverse (30321211312), we get a palindrome (51632423615).

Subtracting 21311212303 from its reverse (30321211312), we obtain a palindrome (9009999009).

The spelling of 21311212303 in words is "twenty-one billion, three hundred eleven million, two hundred twelve thousand, three hundred three".