21103331 has 4 divisors (see below), whose sum is σ = 21357672. Its totient is φ = 20848992.

The previous prime is 21103321. The next prime is 21103337. The reversal of 21103331 is 13330112.

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 21103331 - 2⁶ = 21103267 is a prime.

It is a super-2 number, since 2×21103331² = 890701158591122, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21103337) 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, 127046 + ... + 127211.

It is an arithmetic number, because the mean of its divisors is an integer number (5339418).

Almost surely, 2^21103331 is an apocalyptic number.

21103331 is a deficient number, since it is larger than the sum of its proper divisors (254341).

21103331 is an equidigital number, since it uses as much as digits as its factorization.

21103331 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 254340.

The product of its (nonzero) digits is 54, while the sum is 14.

The square root of 21103331 is about 4593.8361964702. The cubic root of 21103331 is about 276.3441891987.

Adding to 21103331 its reverse (13330112), we get a palindrome (34433443).

The spelling of 21103331 in words is "twenty-one million, one hundred three thousand, three hundred thirty-one".