21331463 has 4 divisors (see below), whose sum is σ = 21356400. Its totient is φ = 21306528.

The previous prime is 21331459. The next prime is 21331469. The reversal of 21331463 is 36413312.

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 21331463 - 2² = 21331459 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21331469) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11138 + ... + 12911.

It is an arithmetic number, because the mean of its divisors is an integer number (5339100).

Almost surely, 2^21331463 is an apocalyptic number.

21331463 is a deficient number, since it is larger than the sum of its proper divisors (24937).

21331463 is an equidigital number, since it uses as much as digits as its factorization.

21331463 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24936.

The product of its digits is 1296, while the sum is 23.

The square root of 21331463 is about 4618.5996795566. The cubic root of 21331463 is about 277.3364043990.

Adding to 21331463 its reverse (36413312), we get a palindrome (57744775).

The spelling of 21331463 in words is "twenty-one million, three hundred thirty-one thousand, four hundred sixty-three".