21331403 has 8 divisors (see below), whose sum is σ = 21841248. Its totient is φ = 20827584.

The previous prime is 21331399. The next prime is 21331451. The reversal of 21331403 is 30413312.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21331403 - 2² = 21331399 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21331103) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6101 + ... + 8937.

It is an arithmetic number, because the mean of its divisors is an integer number (2730156).

Almost surely, 2^21331403 is an apocalyptic number.

21331403 is a deficient number, since it is larger than the sum of its proper divisors (509845).

21331403 is a wasteful number, since it uses less digits than its factorization.

21331403 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3013.

The product of its (nonzero) digits is 216, while the sum is 17.

The square root of 21331403 is about 4618.5931840767. The cubic root of 21331403 is about 277.3361443731.

Adding to 21331403 its reverse (30413312), we get a palindrome (51744715).

The spelling of 21331403 in words is "twenty-one million, three hundred thirty-one thousand, four hundred three".