21331003 has 4 divisors (see below), whose sum is σ = 21344400. Its totient is φ = 21317608.

The previous prime is 21331001. The next prime is 21331021. The reversal of 21331003 is 30013312.

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 21331003 - 2¹ = 21331001 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21331001) 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, 3928 + ... + 7621.

It is an arithmetic number, because the mean of its divisors is an integer number (5336100).

Almost surely, 2^21331003 is an apocalyptic number.

21331003 is a deficient number, since it is larger than the sum of its proper divisors (13397).

21331003 is a wasteful number, since it uses less digits than its factorization.

21331003 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13396.

The product of its (nonzero) digits is 54, while the sum is 13.

The square root of 21331003 is about 4618.5498806444. The cubic root of 21331003 is about 277.3344108545.

Adding to 21331003 its reverse (30013312), we get a palindrome (51344315).

It can be divided in two parts, 2133 and 1003, that added together give a square (3136 = 56²).

The spelling of 21331003 in words is "twenty-one million, three hundred thirty-one thousand, three".