21305001 has 8 divisors (see below), whose sum is σ = 28444480. Its totient is φ = 14184432.

The previous prime is 21304991. The next prime is 21305003. The reversal of 21305001 is 10050312.

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

It is not a de Polignac number, because 21305001 - 2⁷ = 21304873 is a prime.

It is a super-2 number, since 2×21305001² = 907806135220002, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21305003) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1846 + ... + 6783.

It is an arithmetic number, because the mean of its divisors is an integer number (3555560).

Almost surely, 2^21305001 is an apocalyptic number.

It is an amenable number.

21305001 is a deficient number, since it is larger than the sum of its proper divisors (7139479).

21305001 is an equidigital number, since it uses as much as digits as its factorization.

21305001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9455.

The product of its (nonzero) digits is 30, while the sum is 12.

The square root of 21305001 is about 4615.7340694628. The cubic root of 21305001 is about 277.2216769549.

Adding to 21305001 its reverse (10050312), we get a palindrome (31355313).

The spelling of 21305001 in words is "twenty-one million, three hundred five thousand, one".