21320005 has 8 divisors (see below), whose sum is σ = 29238912. Its totient is φ = 14619408.

The previous prime is 21319997. The next prime is 21320021. The reversal of 21320005 is 50002312.

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 21320005 - 2³ = 21319997 is a prime.

It is a super-2 number, since 2×21320005² = 909085226400050, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 304537 + ... + 304606.

It is an arithmetic number, because the mean of its divisors is an integer number (3654864).

Almost surely, 2^21320005 is an apocalyptic number.

It is an amenable number.

21320005 is a deficient number, since it is larger than the sum of its proper divisors (7918907).

21320005 is an equidigital number, since it uses as much as digits as its factorization.

21320005 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 609155.

The product of its (nonzero) digits is 60, while the sum is 13.

The square root of 21320005 is about 4617.3590936811. The cubic root of 21320005 is about 277.2867392689.

Adding to 21320005 its reverse (50002312), we get a palindrome (71322317).

The spelling of 21320005 in words is "twenty-one million, three hundred twenty thousand, five".